diff --git a/app/lib/screens/github_client_id_dialog.dart b/app/lib/screens/github_client_id_dialog.dart
new file mode 100644
index 0000000..0fa07cb
--- /dev/null
+++ b/app/lib/screens/github_client_id_dialog.dart
@@ -0,0 +1,83 @@
+// The "paste your OAuth client id" dialog shown before the device flow.
+//
+// Split out of `github_mirror_screen.dart` for the repo's 250-line cap. A
+// `part` so the class can stay library-private: it is an implementation
+// detail of that screen and nothing else may construct it.
+
+part of 'github_mirror_screen.dart';
+
+/// Dialog shown when "Connect GitHub" is tapped with no OAuth App client id
+/// configured yet. Explains what it is, how to get one, and lets the user
+/// paste it in directly — rather than leaving them to discover a buried
+/// field on their own. Pops the trimmed client id, or null if cancelled.
+class _ClientIdSetupDialog extends StatefulWidget {
+  const _ClientIdSetupDialog();
+
+  @override
+  State<_ClientIdSetupDialog> createState() => _ClientIdSetupDialogState();
+}
+
+class _ClientIdSetupDialogState extends State<_ClientIdSetupDialog> {
+  final _controller = TextEditingController();
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text('One-time GitHub setup needed'),
+      content: SingleChildScrollView(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            const Text(
+              'Diet Guard signs in via a GitHub OAuth App (no password '
+              'typed into this app). You only have to set this up once:',
+            ),
+            const SizedBox(height: 12),
+            const Text(
+              '1. On any device, open '
+              'github.com/settings/developers → "New OAuth App".\n'
+              '2. Name/Homepage/Callback URL can be anything (device flow '
+              "doesn't use the callback) — e.g. "
+              '"Diet Guard" and your GitHub profile URL.\n'
+              '3. Check "Enable Device Flow", then click "Register '
+              'application".\n'
+              "4. Copy the Client ID shown on the app's page and paste it "
+              'below.',
+            ),
+            const SizedBox(height: 12),
+            const Text(
+              'When you connect below, log in with the GitHub account that '
+              'has write access to kuhyx/syncs.',
+            ),
+            const SizedBox(height: 16),
+            TextField(
+              controller: _controller,
+              autofocus: true,
+              decoration: const InputDecoration(labelText: 'Client ID'),
+            ),
+          ],
+        ),
+      ),
+      actions: [
+        TextButton(
+          onPressed: () => Navigator.of(context).pop(),
+          child: const Text('Cancel'),
+        ),
+        FilledButton(
+          onPressed: () {
+            final id = _controller.text.trim();
+            if (id.isNotEmpty) Navigator.of(context).pop(id);
+          },
+          child: const Text('Continue'),
+        ),
+      ],
+    );
+  }
+}
diff --git a/app/lib/screens/github_mirror_actions.dart b/app/lib/screens/github_mirror_actions.dart
new file mode 100644
index 0000000..69e2fb0
--- /dev/null
+++ b/app/lib/screens/github_mirror_actions.dart
@@ -0,0 +1,145 @@
+// Connect / save / test / sync actions for the GitHub mirror screen.
+//
+// Split out of `github_mirror_screen.dart` for the repo's 250-line cap. A
+// `part` rather than a separate library: every one of these methods drives
+// the screen's private state (`_busy`, `_status`, `_storedToken`, the four
+// controllers) and calls its private helpers, none of which are reachable
+// across a library boundary in Dart.
+//
+// A mixin rather than an extension, because these call `setState`, which is
+// `@protected` -- an extension is not a subclass of `State`, so the analyzer
+// (correctly) rejects it there.
+
+part of 'github_mirror_screen.dart';
+
+mixin _GitHubMirrorActions on State<GitHubMirrorScreen> {
+  // The four text controllers stay declared on the State, which creates and
+  // disposes them; the mixin only reads and writes their text.
+  TextEditingController get _ownerController;
+  TextEditingController get _repoController;
+  TextEditingController get _tokenController;
+  TextEditingController get _clientIdController;
+
+  bool _busy = false;
+  String? _status;
+  String _storedToken = '';
+  SyncSettings _currentSettings() {
+    final typed = _tokenController.text.trim();
+    return SyncSettings(
+      owner: _ownerController.text.trim(),
+      repo: _repoController.text.trim(),
+      // The `_storedToken` side is web-only (the wrapper holds the real
+      // token), so it is unreachable from a VM test.
+      token: typed.isEmpty && !SyncSettings.exposesTokenValue
+          // coverage:ignore-line
+          ? _storedToken
+          : typed,
+      clientId: _clientIdController.text.trim(),
+    );
+  }
+  void _showMessage(String message) {
+    if (!mounted) return;
+    setState(() => _status = message);
+  }
+
+  Future<void> _connectGitHub() async {
+    var clientId = _clientIdController.text.trim();
+    if (clientId.isEmpty) {
+      final entered = await showDialog<String>(
+        context: context,
+        builder: (_) => const _ClientIdSetupDialog(),
+      );
+      if (entered == null || entered.isEmpty) return;
+      clientId = entered;
+      if (!mounted) return;
+      setState(() => _clientIdController.text = clientId);
+      await _currentSettings().save();
+    }
+    final auth = createDeviceAuth(clientId, httpClient: widget.httpClient);
+    try {
+      final device = await auth.requestDeviceCode();
+      if (!mounted) return;
+      final token = await showDialog<String>(
+        context: context,
+        barrierDismissible: false,
+        builder: (_) => DeviceCodeDialog(device: device, auth: auth),
+      );
+      if (token != null && token.isNotEmpty) {
+        setState(() {
+          _storedToken = token;
+          if (SyncSettings.exposesTokenValue) _tokenController.text = token;
+        });
+        _showMessage('Connected — syncing…');
+        await _currentSettings().save();
+        await _syncAfterConnect();
+      }
+    } on Exception catch (e) {
+      _showMessage('Could not start device flow: $e');
+    } finally {
+      auth.close();
+    }
+  }
+
+  /// Runs a sync right after connecting so the device-flow token is proven
+  /// to work immediately, with clear confirmation either way.
+  Future<void> _syncAfterConnect() async {
+    final settings = _currentSettings();
+    final client = createGitHubClient(settings, httpClient: widget.httpClient);
+    try {
+      await runSync(await syncBackend(client));
+      await SyncHealth.recordSuccess();
+      _showMessage('Connected and synced.');
+    } on Exception catch (e) {
+      await SyncHealth.recordFailure();
+      _showMessage('Connected, but sync failed: $e');
+    } finally {
+      client.close();
+    }
+  }
+
+  Future<void> _save() async {
+    setState(() => _busy = true);
+    await _currentSettings().save();
+    if (!mounted) return;
+    setState(() => _busy = false);
+    _showMessage('Saved.');
+  }
+
+  Future<void> _testConnection() async {
+    setState(() => _busy = true);
+    final settings = _currentSettings();
+    final client = createGitHubClient(settings, httpClient: widget.httpClient);
+    try {
+      final ok = await client.canAccessRepo();
+      _showMessage(
+        ok ? 'GitHub connection OK.' : 'GitHub connection failed.',
+      );
+    } on Exception catch (e) {
+      _showMessage('GitHub connection failed: $e');
+    } finally {
+      client.close();
+      if (mounted) setState(() => _busy = false);
+    }
+  }
+
+  Future<void> _syncNow() async {
+    setState(() => _busy = true);
+    final settings = _currentSettings();
+    await settings.save();
+    final client = createGitHubClient(settings, httpClient: widget.httpClient);
+    try {
+      await runSync(await syncBackend(client));
+      // Clears any stored failure: this is the button a user reaches
+      // *because* the banner told them syncing had stopped, so a successful
+      // run here must dismiss the warning it caused.
+      await SyncHealth.recordSuccess();
+      _showMessage('Synced.');
+    } on Exception catch (e) {
+      await SyncHealth.recordFailure();
+      _showMessage('Sync failed: $e');
+    } finally {
+      client.close();
+      if (mounted) setState(() => _busy = false);
+    }
+  }
+}
diff --git a/app/lib/screens/github_mirror_screen.dart b/app/lib/screens/github_mirror_screen.dart
index b558c3c..8a44072 100644
--- a/app/lib/screens/github_mirror_screen.dart
+++ b/app/lib/screens/github_mirror_screen.dart
@@ -8,7 +8,7 @@ library;
 
 import 'dart:async';
 
-import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
 import 'package:diet_guard_app/services/github_client_factory.dart';
 import 'package:diet_guard_app/services/sync_health.dart';
 import 'package:diet_guard_app/services/sync_service.dart';
@@ -18,6 +18,9 @@ import 'package:flutter/material.dart';
 import 'package:github_device_auth/github_device_auth.dart';
 import 'package:http/http.dart' as http;
 
+part 'github_client_id_dialog.dart';
+part 'github_mirror_actions.dart';
+
 /// Screen for configuring and triggering the GitHub mirror sync.
 class GitHubMirrorScreen extends StatefulWidget {
   /// Creates a [GitHubMirrorScreen].
@@ -30,14 +33,17 @@ class GitHubMirrorScreen extends StatefulWidget {
   State<GitHubMirrorScreen> createState() => _GitHubMirrorScreenState();
 }
 
-class _GitHubMirrorScreenState extends State<GitHubMirrorScreen> {
+class _GitHubMirrorScreenState extends State<GitHubMirrorScreen>
+    with _GitHubMirrorActions {
+  @override
   final _ownerController = TextEditingController();
+  @override
   final _repoController = TextEditingController();
+  @override
   final _tokenController = TextEditingController();
+  @override
   final _clientIdController = TextEditingController();
   bool _loading = true;
-  bool _busy = false;
-  String? _status;
 
   @override
   void initState() {
@@ -87,129 +93,13 @@ class _GitHubMirrorScreenState extends State<GitHubMirrorScreen> {
 
   /// The token as loaded, so a platform that cannot display it (web) still
   /// round-trips it instead of blanking it on the next save.
-  String _storedToken = '';
 
-  SyncSettings _currentSettings() {
-    final typed = _tokenController.text.trim();
-    return SyncSettings(
-      owner: _ownerController.text.trim(),
-      repo: _repoController.text.trim(),
-      // The `_storedToken` side is web-only (the wrapper holds the real
-      // token), so it is unreachable from a VM test.
-      token: typed.isEmpty && !SyncSettings.exposesTokenValue
-          // coverage:ignore-line
-          ? _storedToken
-          : typed,
-      clientId: _clientIdController.text.trim(),
-    );
-  }
 
-  void _showMessage(String message) {
-    if (!mounted) return;
-    setState(() => _status = message);
-  }
+
+
 
   /// Runs the OAuth device flow and, on success, fills in the token field.
-  Future<void> _connectGitHub() async {
-    var clientId = _clientIdController.text.trim();
-    if (clientId.isEmpty) {
-      final entered = await showDialog<String>(
-        context: context,
-        builder: (_) => const _ClientIdSetupDialog(),
-      );
-      if (entered == null || entered.isEmpty) return;
-      clientId = entered;
-      if (!mounted) return;
-      setState(() => _clientIdController.text = clientId);
-      await _currentSettings().save();
-    }
-    final auth = createDeviceAuth(clientId, httpClient: widget.httpClient);
-    try {
-      final device = await auth.requestDeviceCode();
-      if (!mounted) return;
-      final token = await showDialog<String>(
-        context: context,
-        barrierDismissible: false,
-        builder: (_) => DeviceCodeDialog(device: device, auth: auth),
-      );
-      if (token != null && token.isNotEmpty) {
-        setState(() {
-          _storedToken = token;
-          if (SyncSettings.exposesTokenValue) _tokenController.text = token;
-        });
-        _showMessage('Connected — syncing…');
-        await _currentSettings().save();
-        await _syncAfterConnect();
-      }
-    } on Exception catch (e) {
-      _showMessage('Could not start device flow: $e');
-    } finally {
-      auth.close();
-    }
-  }
 
-  /// Runs a sync right after connecting so the device-flow token is proven
-  /// to work immediately, with clear confirmation either way.
-  Future<void> _syncAfterConnect() async {
-    final settings = _currentSettings();
-    final client = createGitHubClient(settings, httpClient: widget.httpClient);
-    try {
-      await runSync(await syncBackend(client));
-      await SyncHealth.recordSuccess();
-      _showMessage('Connected and synced.');
-    } on Exception catch (e) {
-      await SyncHealth.recordFailure();
-      _showMessage('Connected, but sync failed: $e');
-    } finally {
-      client.close();
-    }
-  }
-
-  Future<void> _save() async {
-    setState(() => _busy = true);
-    await _currentSettings().save();
-    if (!mounted) return;
-    setState(() => _busy = false);
-    _showMessage('Saved.');
-  }
-
-  Future<void> _testConnection() async {
-    setState(() => _busy = true);
-    final settings = _currentSettings();
-    final client = createGitHubClient(settings, httpClient: widget.httpClient);
-    try {
-      final ok = await client.canAccessRepo();
-      _showMessage(
-        ok ? 'GitHub connection OK.' : 'GitHub connection failed.',
-      );
-    } on Exception catch (e) {
-      _showMessage('GitHub connection failed: $e');
-    } finally {
-      client.close();
-      if (mounted) setState(() => _busy = false);
-    }
-  }
-
-  Future<void> _syncNow() async {
-    setState(() => _busy = true);
-    final settings = _currentSettings();
-    await settings.save();
-    final client = createGitHubClient(settings, httpClient: widget.httpClient);
-    try {
-      await runSync(await syncBackend(client));
-      // Clears any stored failure: this is the button a user reaches
-      // *because* the banner told them syncing had stopped, so a successful
-      // run here must dismiss the warning it caused.
-      await SyncHealth.recordSuccess();
-      _showMessage('Synced.');
-    } on Exception catch (e) {
-      await SyncHealth.recordFailure();
-      _showMessage('Sync failed: $e');
-    } finally {
-      client.close();
-      if (mounted) setState(() => _busy = false);
-    }
-  }
 
   @override
   Widget build(BuildContext context) {
@@ -313,79 +203,3 @@ class _GitHubMirrorScreenState extends State<GitHubMirrorScreen> {
     );
   }
 }
-
-/// Dialog shown when "Connect GitHub" is tapped with no OAuth App client id
-/// configured yet. Explains what it is, how to get one, and lets the user
-/// paste it in directly — rather than leaving them to discover a buried
-/// field on their own. Pops the trimmed client id, or null if cancelled.
-class _ClientIdSetupDialog extends StatefulWidget {
-  const _ClientIdSetupDialog();
-
-  @override
-  State<_ClientIdSetupDialog> createState() => _ClientIdSetupDialogState();
-}
-
-class _ClientIdSetupDialogState extends State<_ClientIdSetupDialog> {
-  final _controller = TextEditingController();
-
-  @override
-  void dispose() {
-    _controller.dispose();
-    super.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return AlertDialog(
-      title: const Text('One-time GitHub setup needed'),
-      content: SingleChildScrollView(
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            const Text(
-              'Diet Guard signs in via a GitHub OAuth App (no password '
-              'typed into this app). You only have to set this up once:',
-            ),
-            const SizedBox(height: 12),
-            const Text(
-              '1. On any device, open '
-              'github.com/settings/developers → "New OAuth App".\n'
-              '2. Name/Homepage/Callback URL can be anything (device flow '
-              "doesn't use the callback) — e.g. "
-              '"Diet Guard" and your GitHub profile URL.\n'
-              '3. Check "Enable Device Flow", then click "Register '
-              'application".\n'
-              "4. Copy the Client ID shown on the app's page and paste it "
-              'below.',
-            ),
-            const SizedBox(height: 12),
-            const Text(
-              'When you connect below, log in with the GitHub account that '
-              'has write access to kuhyx/syncs.',
-            ),
-            const SizedBox(height: 16),
-            TextField(
-              controller: _controller,
-              autofocus: true,
-              decoration: const InputDecoration(labelText: 'Client ID'),
-            ),
-          ],
-        ),
-      ),
-      actions: [
-        TextButton(
-          onPressed: () => Navigator.of(context).pop(),
-          child: const Text('Cancel'),
-        ),
-        FilledButton(
-          onPressed: () {
-            final id = _controller.text.trim();
-            if (id.isNotEmpty) Navigator.of(context).pop(id);
-          },
-          child: const Text('Continue'),
-        ),
-      ],
-    );
-  }
-}
diff --git a/app/lib/screens/log_meal_sync_mixin.dart b/app/lib/screens/log_meal_sync_mixin.dart
index 97e06de..791effc 100644
--- a/app/lib/screens/log_meal_sync_mixin.dart
+++ b/app/lib/screens/log_meal_sync_mixin.dart
@@ -2,7 +2,7 @@ import 'dart:async';
 import 'dart:developer';
 
 import 'package:diet_guard_app/services/background_tasks.dart';
-import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
 import 'package:diet_guard_app/services/github_client_factory.dart';
 import 'package:diet_guard_app/services/log_storage_service.dart';
 import 'package:diet_guard_app/services/sync_health.dart';
diff --git a/app/lib/screens/settings_kcal_goal.dart b/app/lib/screens/settings_kcal_goal.dart
new file mode 100644
index 0000000..7a22eb9
--- /dev/null
+++ b/app/lib/screens/settings_kcal_goal.dart
@@ -0,0 +1,62 @@
+// The debounced daily-kcal-goal field and the battery-exemption request.
+//
+// Split out of `settings_screen.dart` for the repo's 250-line cap. A `part`
+// mixin: these drive the screen's private state and call `setState`, which is
+// `@protected` and therefore unreachable from an extension.
+
+part of 'settings_screen.dart';
+
+mixin _SettingsKcalGoal on State<SettingsScreen> {
+  String? _status;
+
+  void _showMessage(String message) {
+    if (!mounted) return;
+    setState(() => _status = message);
+  }
+
+  Timer? _kcalGoalDebounce;
+  int? _pendingKcalGoal;
+
+  /// Persists the pending goal, if any, and clears it.
+  void _flushKcalGoal() {
+    final goal = _pendingKcalGoal;
+    if (goal == null) return;
+    _pendingKcalGoal = null;
+    unawaited(AppSettingsService.instance.saveDailyKcalGoal(goal));
+  }
+
+  /// Saves the typed goal once typing settles.
+  ///
+  /// Debounced because every keystroke would otherwise be a real edit:
+  /// typing "2000" saved 2, 20, 200, 2000 in turn, and a sync tick landing
+  /// between keystrokes would push a nonsense budget to the other device.
+  void _onKcalGoalChanged(String value) {
+    _kcalGoalDebounce?.cancel();
+    final goal = int.tryParse(value);
+    if (goal == null || goal <= 0) return;
+    _pendingKcalGoal = goal;
+    _kcalGoalDebounce = Timer(
+      const Duration(milliseconds: 600),
+      _flushKcalGoal,
+    );
+  }
+
+  /// Requests exemption from OEM battery optimization (MIUI, some Samsung
+  /// configs), which can otherwise degrade the 15-minute background-check
+  /// reliability well past its accepted ±15 min target.
+  Future<void> _requestBatteryExemption() async {
+    final request =
+        widget.requestBatteryExemption ??
+        () => Permission.ignoreBatteryOptimizations.request();
+    try {
+      final status = await request();
+      _showMessage(
+        status.isGranted
+            ? 'Battery optimization exemption granted.'
+            : 'Exemption not granted -- notifications may be delayed.',
+      );
+    } on Exception catch (e) {
+      _showMessage('Could not request exemption: $e');
+    }
+  }
+}
diff --git a/app/lib/screens/settings_screen.dart b/app/lib/screens/settings_screen.dart
index 8c6fdfa..eddab4c 100644
--- a/app/lib/screens/settings_screen.dart
+++ b/app/lib/screens/settings_screen.dart
@@ -14,6 +14,7 @@ import 'package:crdt_sync/crdt_sync.dart';
 import 'package:diet_guard_app/screens/github_mirror_screen.dart';
 import 'package:diet_guard_app/services/app_settings_service.dart';
 import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
 import 'package:diet_guard_app/services/google_sign_in_backend.dart';
 import 'package:diet_guard_app/ui/theme.dart';
 import 'package:flutter/foundation.dart';
@@ -23,6 +24,8 @@ import 'package:http/http.dart' as http;
 import 'package:permission_handler/permission_handler.dart';
 import 'package:sync_settings_ui/sync_settings_ui.dart';
 
+part 'settings_kcal_goal.dart';
+
 /// Screen for app-specific settings and links to sync configuration.
 class SettingsScreen extends StatefulWidget {
   /// Creates a [SettingsScreen].
@@ -87,7 +90,8 @@ class SettingsScreen extends StatefulWidget {
   State<SettingsScreen> createState() => _SettingsScreenState();
 }
 
-class _SettingsScreenState extends State<SettingsScreen> {
+class _SettingsScreenState extends State<SettingsScreen>
+    with _SettingsKcalGoal {
   final _kcalGoalController = TextEditingController();
 
   @override
@@ -106,59 +110,6 @@ class _SettingsScreenState extends State<SettingsScreen> {
     super.dispose();
   }
 
-  Timer? _kcalGoalDebounce;
-  int? _pendingKcalGoal;
-
-  /// Persists the pending goal, if any, and clears it.
-  void _flushKcalGoal() {
-    final goal = _pendingKcalGoal;
-    if (goal == null) return;
-    _pendingKcalGoal = null;
-    unawaited(AppSettingsService.instance.saveDailyKcalGoal(goal));
-  }
-
-  /// Saves the typed goal once typing settles.
-  ///
-  /// Debounced because every keystroke would otherwise be a real edit:
-  /// typing "2000" saved 2, 20, 200, 2000 in turn, and a sync tick landing
-  /// between keystrokes would push a nonsense budget to the other device.
-  void _onKcalGoalChanged(String value) {
-    _kcalGoalDebounce?.cancel();
-    final goal = int.tryParse(value);
-    if (goal == null || goal <= 0) return;
-    _pendingKcalGoal = goal;
-    _kcalGoalDebounce = Timer(
-      const Duration(milliseconds: 600),
-      _flushKcalGoal,
-    );
-  }
-
-  /// Requests exemption from OEM battery optimization (MIUI, some Samsung
-  /// configs), which can otherwise degrade the 15-minute background-check
-  /// reliability well past its accepted ±15 min target.
-  Future<void> _requestBatteryExemption() async {
-    final request =
-        widget.requestBatteryExemption ??
-        () => Permission.ignoreBatteryOptimizations.request();
-    try {
-      final status = await request();
-      _showMessage(
-        status.isGranted
-            ? 'Battery optimization exemption granted.'
-            : 'Exemption not granted -- notifications may be delayed.',
-      );
-    } on Exception catch (e) {
-      _showMessage('Could not request exemption: $e');
-    }
-  }
-
-  String? _status;
-
-  void _showMessage(String message) {
-    if (!mounted) return;
-    setState(() => _status = message);
-  }
-
   /// True on the one platform with OEM battery optimization to exempt from.
   ///
   /// Uses [defaultTargetPlatform] rather than `Platform.isAndroid` because
diff --git a/app/lib/services/background_sync_service.dart b/app/lib/services/background_sync_service.dart
index e307dc8..663557f 100644
--- a/app/lib/services/background_sync_service.dart
+++ b/app/lib/services/background_sync_service.dart
@@ -8,7 +8,7 @@ library;
 import 'dart:developer';
 import 'package:diet_guard_app/services/app_settings_service.dart';
 import 'package:diet_guard_app/services/budget_history_service.dart';
-import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
 import 'package:diet_guard_app/services/foodbank_service.dart';
 import 'package:diet_guard_app/services/github_client_factory.dart';
 import 'package:diet_guard_app/services/log_storage_service.dart';
diff --git a/app/lib/services/firebase_backend.dart b/app/lib/services/firebase_backend.dart
index 7e55ec8..0288c6f 100644
--- a/app/lib/services/firebase_backend.dart
+++ b/app/lib/services/firebase_backend.dart
@@ -14,9 +14,7 @@ library;
 
 import 'dart:developer';
 import 'package:crdt_sync/crdt_sync.dart';
-import 'package:diet_guard_app/services/google_sign_in_backend.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
-import 'package:http/http.dart' as http;
 
 /// The shared `kuhy-syncs` project.
 ///
@@ -99,184 +97,10 @@ Future<void> clearAccount() async {
   await credentialStore().clear();
 }
 
-/// Returns a signed-in Firebase client, or null when not configured.
+/// Drops just the stored account marker, leaving the opt-out flag alone.
 ///
-/// Signs in with the stored password only when there is no cached refresh
-/// token, so the usual path costs no authentication round trip.
-Future<FirebaseRestClient?> openFirebase() async {
-  final account = await loadAccount();
-  if (account == null) {
-    // A stored refresh token is a signed-in device, even with no account
-    // marker beside it. Treating the marker as the source of truth is what
-    // turned one missing write into "syncs over GitHub and 401s forever":
-    // the credential that actually authenticates was sitting in the keystore
-    // the whole time, unused. Ask the store directly before giving up.
-    return _clientFromStoredSession();
-  }
-  try {
-    return await firebaseClientFor(
-      config: kProject.configFor(account.email),
-      store: credentialStore(),
-      // A Google-provisioned account stores an empty password.
-      // Passing '' would make firebaseClientFor treat it as a usable
-      // credential and sign in with it, which fails; null correctly
-      // means "no password on this device".
-      password: account.password.isEmpty ? null : account.password,
-      // Deliberately NOT offering Google here. This path runs from background
-      // timers and, in some apps, before runApp -- offering it would let a
-      // non-interactive tick raise the OS account picker with no user action
-      // behind it. Interactive sign-in uses openFirebaseWithGoogle instead.
-      expectedUid: kSyncUid,
-    );
-  } on Object catch (error, stackTrace) {
-    // Unreachable keystore or a rejected sign-in must not fail the tick: the
-    // app keeps syncing over GitHub, exactly as before the cutover.
-    // Broader than Exception because an uninitialised platform binding
-    // raises a FlutterError, which is an Error.
-    //
-    // Never silent, for the same reason loadAccount() above says why: a
-    // signed-in-but-failing device looked exactly like an unconfigured one,
-    // which is how the phone went days without publishing a single meal.
-    log(
-      'openFirebase failed; falling back to the GitHub mirror',
-      level: 1000,
-      error: error,
-      stackTrace: stackTrace,
-    );
-    return null;
-  }
-}
-
-/// Whether this device can actually authenticate against Firebase.
-///
-/// True when either half of the state is present: the account marker
-/// [loadAccount] reads, or a stored refresh token. The token is the half that
-/// matters -- it is what signs requests -- so a settings screen that reports
-/// the marker alone calls a working device "Not connected", which is how a
-/// phone that was in fact syncing looked broken for a whole session.
-Future<bool> isFirebaseConfigured() async {
-  try {
-    final auth = FirebaseTokenProvider(
-      apiKey: kProject.apiKey,
-      store: credentialStore(),
-    );
-    if (await auth.hasSession()) return true;
-    // storedAccount, not loadAccount: on Android the latter falls back to the
-    // desktop wrapper's /sync-account route, which resolves to file:/// and
-    // throws "No host specified in URI" -- observed on the phone, where it
-    // turned a successful sign-in into "Google sign-in failed".
-    if (await storedAccount() == null) return false;
-    // A marker with no session behind it cannot sign a single request. Drop
-    // just the marker so the settings screen offers a sign-in instead of a
-    // dead banner -- not clearAccount(), which also sets the opt-out flag and
-    // would stop the desktop wrapper re-provisioning after the next sign-in.
-    await _secure.delete(key: kFirebaseAccountKey);
-    return false;
-  } on Object catch (error, stackTrace) {
-    log(
-      'session probe failed; reporting this device as not configured',
-      level: 1000,
-      error: error,
-      stackTrace: stackTrace,
-    );
-    return false;
-  }
-}
-
-/// Returns a client built from the keystore's refresh token alone, or null.
-///
-/// The recovery path for a device that has a live session but no account
-/// marker -- the state a Google sign-in used to leave behind. Costs one
-/// keystore read and no network round trip when there is no session, so it is
-/// safe on the background-tick path that [openFirebase] also serves.
-///
-/// Does not re-save the account: a device that reaches this is already signed
-/// in, and writing a marker from a read path would hide the condition rather
-/// than repair it. [openFirebaseWithGoogle] is what writes the marker.
-Future<FirebaseRestClient?> _clientFromStoredSession() async {
-  try {
-    final auth = FirebaseTokenProvider(
-      apiKey: kProject.apiKey,
-      store: credentialStore(),
-    );
-    if (!await auth.hasSession()) return null;
-    return FirebaseRestClient(databaseUrl: kProject.databaseUrl, auth: auth);
-  } on Object catch (error, stackTrace) {
-    // Same contract as openFirebase's own catch: an unreachable keystore
-    // degrades to the GitHub mirror instead of failing the tick, but says so.
-    log(
-      'stored-session recovery failed; falling back to the GitHub mirror',
-      level: 1000,
-      error: error,
-      stackTrace: stackTrace,
-    );
-    return null;
-  }
-}
-
-/// Signs in with Google alone, for a device that has no account stored yet.
-///
-/// This is the one-tap path: [openFirebase] needs an account in the keystore
-/// to know which email to use, but a fresh install has none. The Google token
-/// carries the identity, so nothing needs to be typed.
-///
-/// The account is stored under the email **Firebase reports**, never one read
-/// from the UI: a fresh install has no email anywhere on the device, so taking
-/// it from a text field would persist an empty account and send the next
-/// launch down the password path with ''.
-///
-/// Returns null when the user dismisses the picker; throws [FirebaseAuthError]
-/// when Google succeeds but resolves to a uid the security rules do not pin,
-/// which would otherwise authenticate fine and then be denied every read and
-/// write with no other symptom.
-Future<FirebaseRestClient?> openFirebaseWithGoogle({
-  Future<String?> Function()? tokenFetcher,
-  Future<void> Function(FirebaseAccount)? accountSaver,
-  http.Client? httpClient,
-}) async {
-  final token = await (tokenFetcher ?? googleIdToken)();
-  if (token == null) return null;
-  final auth = FirebaseTokenProvider(
-    apiKey: kProject.apiKey,
-    store: credentialStore(),
-    httpClient: httpClient,
-  );
-  final email = await auth.signInWithGoogle(
-    idToken: token,
-    expectedUid: kSyncUid,
-  );
-  // The account must be saved unconditionally, and the signed-in email is not
-  // reliable enough to gate it on. `signInWithIdp` omits `email` whenever the
-  // Google account hides it, so gating the save on a non-null email produced
-  // the worst possible outcome: this call returned a perfectly working client
-  // -- "Connected to Firebase" -- while the device stayed unconfigured, so the
-  // next launch found no account, `openFirebase()` returned null, and
-  // `syncBackend()` silently dropped to GitHub-only and 401'd. The session is
-  // already durable at this point (`signInWithGoogle` stores the refresh token
-  // via `_adopt`); only this marker was missing, which is exactly why the
-  // failure survived a restart and looked like a sign-in that never happened.
-  //
-  // The email is a display convenience, not the credential -- the refresh
-  // token in the keystore is. An empty string is the honest value when Google
-  // withholds it, and `openFirebase()` already treats an empty password as
-  // "no password on this device" and authenticates from the stored token.
-  await (accountSaver ?? saveAccount)(
-    FirebaseAccount(email: email ?? '', password: ''),
-  );
-  return FirebaseRestClient(databaseUrl: kProject.databaseUrl, auth: auth);
-}
-
-// coverage:ignore-end
-
-/// Wraps [github] so Firebase is primary and GitHub is kept as a mirror.
-///
-/// Returns [github] unchanged when this device has not been set up for
-/// Firebase — a normal state during the cutover, not an error, and also the
-/// rollback. Reads union both, so a device that has not moved yet still
-/// converges.
-Future<RemoteStore> syncBackend(RemoteStore github) async {
-  final firebase = await openFirebase();
-  return firebase == null
-      ? github
-      : MirrorStore(primary: firebase, mirror: github);
-}
+/// Deliberately narrower than [clearAccount]: a marker with no session behind
+/// it cannot sign a request, but setting the opt-out flag as well would stop
+/// the desktop wrapper re-provisioning after the next sign-in.
+Future<void> forgetAccountMarker() =>
+    _secure.delete(key: kFirebaseAccountKey);
diff --git a/app/lib/services/firebase_client.dart b/app/lib/services/firebase_client.dart
new file mode 100644
index 0000000..8d47351
--- /dev/null
+++ b/app/lib/services/firebase_client.dart
@@ -0,0 +1,197 @@
+/// Opening an authenticated Firebase REST client, and choosing a backend.
+///
+/// Split out of `firebase_backend.dart` for the repo's 250-line cap. That
+/// module owns the project constants and the keystore-backed account record;
+/// this one turns a stored account (or a Google sign-in) into a live client,
+/// and decides whether a sync tick runs against Firebase or the GitHub
+/// mirror.
+library;
+
+import 'dart:developer';
+
+import 'package:crdt_sync/crdt_sync.dart';
+import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/google_sign_in_backend.dart';
+import 'package:http/http.dart' as http;
+
+/// Returns a signed-in Firebase client, or null when not configured.
+///
+/// Signs in with the stored password only when there is no cached refresh
+/// token, so the usual path costs no authentication round trip.
+Future<FirebaseRestClient?> openFirebase() async {
+  final account = await loadAccount();
+  if (account == null) {
+    // A stored refresh token is a signed-in device, even with no account
+    // marker beside it. Treating the marker as the source of truth is what
+    // turned one missing write into "syncs over GitHub and 401s forever":
+    // the credential that actually authenticates was sitting in the keystore
+    // the whole time, unused. Ask the store directly before giving up.
+    return _clientFromStoredSession();
+  }
+  try {
+    return await firebaseClientFor(
+      config: kProject.configFor(account.email),
+      store: credentialStore(),
+      // A Google-provisioned account stores an empty password.
+      // Passing '' would make firebaseClientFor treat it as a usable
+      // credential and sign in with it, which fails; null correctly
+      // means "no password on this device".
+      password: account.password.isEmpty ? null : account.password,
+      // Deliberately NOT offering Google here. This path runs from background
+      // timers and, in some apps, before runApp -- offering it would let a
+      // non-interactive tick raise the OS account picker with no user action
+      // behind it. Interactive sign-in uses openFirebaseWithGoogle instead.
+      expectedUid: kSyncUid,
+    );
+  } on Object catch (error, stackTrace) {
+    // Unreachable keystore or a rejected sign-in must not fail the tick: the
+    // app keeps syncing over GitHub, exactly as before the cutover.
+    // Broader than Exception because an uninitialised platform binding
+    // raises a FlutterError, which is an Error.
+    //
+    // Never silent, for the same reason loadAccount() above says why: a
+    // signed-in-but-failing device looked exactly like an unconfigured one,
+    // which is how the phone went days without publishing a single meal.
+    log(
+      'openFirebase failed; falling back to the GitHub mirror',
+      level: 1000,
+      error: error,
+      stackTrace: stackTrace,
+    );
+    return null;
+  }
+}
+
+/// Whether this device can actually authenticate against Firebase.
+///
+/// True when either half of the state is present: the account marker
+/// [loadAccount] reads, or a stored refresh token. The token is the half that
+/// matters -- it is what signs requests -- so a settings screen that reports
+/// the marker alone calls a working device "Not connected", which is how a
+/// phone that was in fact syncing looked broken for a whole session.
+Future<bool> isFirebaseConfigured() async {
+  try {
+    final auth = FirebaseTokenProvider(
+      apiKey: kProject.apiKey,
+      store: credentialStore(),
+    );
+    if (await auth.hasSession()) return true;
+    // storedAccount, not loadAccount: on Android the latter falls back to the
+    // desktop wrapper's /sync-account route, which resolves to file:/// and
+    // throws "No host specified in URI" -- observed on the phone, where it
+    // turned a successful sign-in into "Google sign-in failed".
+    if (await storedAccount() == null) return false;
+    // A marker with no session behind it cannot sign a single request. Drop
+    // just the marker so the settings screen offers a sign-in instead of a
+    // dead banner -- not clearAccount(), which also sets the opt-out flag and
+    // would stop the desktop wrapper re-provisioning after the next sign-in.
+    await forgetAccountMarker();
+    return false;
+  } on Object catch (error, stackTrace) {
+    log(
+      'session probe failed; reporting this device as not configured',
+      level: 1000,
+      error: error,
+      stackTrace: stackTrace,
+    );
+    return false;
+  }
+}
+
+/// Returns a client built from the keystore's refresh token alone, or null.
+///
+/// The recovery path for a device that has a live session but no account
+/// marker -- the state a Google sign-in used to leave behind. Costs one
+/// keystore read and no network round trip when there is no session, so it is
+/// safe on the background-tick path that [openFirebase] also serves.
+///
+/// Does not re-save the account: a device that reaches this is already signed
+/// in, and writing a marker from a read path would hide the condition rather
+/// than repair it. [openFirebaseWithGoogle] is what writes the marker.
+Future<FirebaseRestClient?> _clientFromStoredSession() async {
+  try {
+    final auth = FirebaseTokenProvider(
+      apiKey: kProject.apiKey,
+      store: credentialStore(),
+    );
+    if (!await auth.hasSession()) return null;
+    return FirebaseRestClient(databaseUrl: kProject.databaseUrl, auth: auth);
+  } on Object catch (error, stackTrace) {
+    // Same contract as openFirebase's own catch: an unreachable keystore
+    // degrades to the GitHub mirror instead of failing the tick, but says so.
+    log(
+      'stored-session recovery failed; falling back to the GitHub mirror',
+      level: 1000,
+      error: error,
+      stackTrace: stackTrace,
+    );
+    return null;
+  }
+}
+
+/// Signs in with Google alone, for a device that has no account stored yet.
+///
+/// This is the one-tap path: [openFirebase] needs an account in the keystore
+/// to know which email to use, but a fresh install has none. The Google token
+/// carries the identity, so nothing needs to be typed.
+///
+/// The account is stored under the email **Firebase reports**, never one read
+/// from the UI: a fresh install has no email anywhere on the device, so taking
+/// it from a text field would persist an empty account and send the next
+/// launch down the password path with ''.
+///
+/// Returns null when the user dismisses the picker; throws [FirebaseAuthError]
+/// when Google succeeds but resolves to a uid the security rules do not pin,
+/// which would otherwise authenticate fine and then be denied every read and
+/// write with no other symptom.
+Future<FirebaseRestClient?> openFirebaseWithGoogle({
+  Future<String?> Function()? tokenFetcher,
+  Future<void> Function(FirebaseAccount)? accountSaver,
+  http.Client? httpClient,
+}) async {
+  final token = await (tokenFetcher ?? googleIdToken)();
+  if (token == null) return null;
+  final auth = FirebaseTokenProvider(
+    apiKey: kProject.apiKey,
+    store: credentialStore(),
+    httpClient: httpClient,
+  );
+  final email = await auth.signInWithGoogle(
+    idToken: token,
+    expectedUid: kSyncUid,
+  );
+  // The account must be saved unconditionally, and the signed-in email is not
+  // reliable enough to gate it on. `signInWithIdp` omits `email` whenever the
+  // Google account hides it, so gating the save on a non-null email produced
+  // the worst possible outcome: this call returned a perfectly working client
+  // -- "Connected to Firebase" -- while the device stayed unconfigured, so the
+  // next launch found no account, `openFirebase()` returned null, and
+  // `syncBackend()` silently dropped to GitHub-only and 401'd. The session is
+  // already durable at this point (`signInWithGoogle` stores the refresh token
+  // via `_adopt`); only this marker was missing, which is exactly why the
+  // failure survived a restart and looked like a sign-in that never happened.
+  //
+  // The email is a display convenience, not the credential -- the refresh
+  // token in the keystore is. An empty string is the honest value when Google
+  // withholds it, and `openFirebase()` already treats an empty password as
+  // "no password on this device" and authenticates from the stored token.
+  await (accountSaver ?? saveAccount)(
+    FirebaseAccount(email: email ?? '', password: ''),
+  );
+  return FirebaseRestClient(databaseUrl: kProject.databaseUrl, auth: auth);
+}
+
+// coverage:ignore-end
+
+/// Wraps [github] so Firebase is primary and GitHub is kept as a mirror.
+///
+/// Returns [github] unchanged when this device has not been set up for
+/// Firebase — a normal state during the cutover, not an error, and also the
+/// rollback. Reads union both, so a device that has not moved yet still
+/// converges.
+Future<RemoteStore> syncBackend(RemoteStore github) async {
+  final firebase = await openFirebase();
+  return firebase == null
+      ? github
+      : MirrorStore(primary: firebase, mirror: github);
+}
diff --git a/app/lib/services/foodbank_service.dart b/app/lib/services/foodbank_service.dart
index a541747..059b83d 100644
--- a/app/lib/services/foodbank_service.dart
+++ b/app/lib/services/foodbank_service.dart
@@ -15,6 +15,8 @@ import 'package:diet_guard_app/services/fuzzy.dart';
 import 'package:diet_guard_app/services/log_storage_service.dart';
 import 'package:flutter/foundation.dart';
 
+part 'foodbank_service_manual.dart';
+
 /// Below this similarity ratio a non-substring candidate is dropped.
 /// Mirrors `_foodbank._FUZZY_THRESHOLD`.
 const double fuzzyThreshold = 0.6;
@@ -204,111 +206,4 @@ class FoodBankService {
     await writeBank(bank);
     return bank;
   }
-
-  // ---------------------------------------------------------------------------
-  // Manual bank (food items added directly without logging them as eaten)
-  // ---------------------------------------------------------------------------
-
-  Future<Map<String, FoodBankRecord>> _readManualBank() =>
-      _readBank(manualDocumentName);
-
-  Future<void> _writeManualBank(Map<String, FoodBankRecord> bank) =>
-      _writeBank(manualDocumentName, bank);
-
-  /// Adds or updates [record] in the manually-curated bank without logging it
-  /// as eaten. A repeated call with the same normalized name overwrites the
-  /// previous entry.
-  Future<void> addManualEntry(FoodBankRecord record) async {
-    final bank = await _readManualBank();
-    bank[_normalize(record.desc)] = FoodBankRecord(
-      desc: record.desc,
-      kcal: record.kcal,
-      proteinG: record.proteinG,
-      carbsG: record.carbsG,
-      fatG: record.fatG,
-      grams: record.grams,
-      count: record.count,
-      components: record.components,
-      // Stamped here, not by callers: this is what the cross-device merge
-      // orders by, so it must be set on every write without exception.
-      editedAt: DateTime.now().toIso8601String(),
-    );
-    await _writeManualBank(bank);
-  }
-
-  /// Returns the hand-curated bank, for the sync layer.
-  Future<Map<String, FoodBankRecord>> readManualBank() => _readManualBank();
-
-  /// Replaces the hand-curated bank with a merge result from the sync layer.
-  Future<void> applyMergedManualBank(Map<String, FoodBankRecord> bank) =>
-      _writeManualBank(bank);
-
-  /// All known food records: log-derived entries merged with manually-added
-  /// ones, sorted by count descending.
-  ///
-  /// Log-derived records (from [readBank]) take precedence over manual records
-  /// with the same normalized name.
-  Future<List<FoodBankRecord>> mergedEntries() async {
-    final logBank = await readBank();
-    final manualBank = await _readManualBank();
-    final merged = <String, FoodBankRecord>{...manualBank, ...logBank};
-    return merged.values.toList()..sort((a, b) => b.count.compareTo(a.count));
-  }
-
-  // ---------------------------------------------------------------------------
-  // Search
-  // ---------------------------------------------------------------------------
-
-  /// Returns banked foods matching [query], best match first.
-  ///
-  /// An empty query returns the most-logged foods. Mirrors
-  /// `_foodbank.search_foods`. Searches both log-derived and manually-added
-  /// entries; log-derived entries win on name collision.
-  Future<List<FoodSuggestion>> search(
-    String query, {
-    int limit = defaultSuggestions,
-  }) async {
-    final logBank = await readBank();
-    final manualBank = await _readManualBank();
-    final bank = <String, FoodBankRecord>{...manualBank, ...logBank};
-    final normalized = _normalize(query);
-    if (normalized.isEmpty) return _rankedAll(bank, limit);
-
-    final scored = <(double score, double count, FoodSuggestion suggestion)>[];
-    for (final mapEntry in bank.entries) {
-      final score = matchScore(normalized, mapEntry.key);
-      if (score < fuzzyThreshold) continue;
-      final record = mapEntry.value;
-      scored.add((
-        score,
-        record.count,
-        FoodSuggestion(
-          name: _displayName(record, mapEntry.key),
-          nutrition: _recordToNutrition(record),
-        ),
-      ));
-    }
-    scored.sort((a, b) {
-      final byScore = b.$1.compareTo(a.$1);
-      return byScore != 0 ? byScore : b.$2.compareTo(a.$2);
-    });
-    return scored.take(limit).map((s) => s.$3).toList();
-  }
-
-  List<FoodSuggestion> _rankedAll(
-    Map<String, FoodBankRecord> bank,
-    int limit,
-  ) {
-    final ranked = bank.entries.toList()
-      ..sort((a, b) => b.value.count.compareTo(a.value.count));
-    return ranked
-        .take(limit)
-        .map(
-          (mapEntry) => FoodSuggestion(
-            name: _displayName(mapEntry.value, mapEntry.key),
-            nutrition: _recordToNutrition(mapEntry.value),
-          ),
-        )
-        .toList();
-  }
 }
diff --git a/app/lib/services/foodbank_service_manual.dart b/app/lib/services/foodbank_service_manual.dart
new file mode 100644
index 0000000..92b1ba8
--- /dev/null
+++ b/app/lib/services/foodbank_service_manual.dart
@@ -0,0 +1,121 @@
+// The curated ("manual") half of the food bank, plus ranked search across
+// both halves.
+//
+// Split out of `foodbank_service.dart` for the repo's 250-line cap. It is a
+// `part` rather than a separate library because these methods reach the
+// service's private members (`_readBank`, `_writeBank`, `_normalize`,
+// `_recordToNutrition`), which a `library`-private name makes invisible
+// across a file boundary -- and widening them to public just to split a file
+// would leak internals the rest of the app has no business calling.
+
+part of 'foodbank_service.dart';
+
+/// The curated bank and cross-bank search, split out for the file cap.
+extension FoodBankManual on FoodBankService {
+  // ---------------------------------------------------------------------------
+  // Manual bank (food items added directly without logging them as eaten)
+  // ---------------------------------------------------------------------------
+
+  Future<Map<String, FoodBankRecord>> _readManualBank() =>
+      _readBank(FoodBankService.manualDocumentName);
+
+  Future<void> _writeManualBank(Map<String, FoodBankRecord> bank) =>
+      _writeBank(FoodBankService.manualDocumentName, bank);
+
+  /// Adds or updates [record] in the manually-curated bank without logging it
+  /// as eaten. A repeated call with the same normalized name overwrites the
+  /// previous entry.
+  Future<void> addManualEntry(FoodBankRecord record) async {
+    final bank = await _readManualBank();
+    bank[_normalize(record.desc)] = FoodBankRecord(
+      desc: record.desc,
+      kcal: record.kcal,
+      proteinG: record.proteinG,
+      carbsG: record.carbsG,
+      fatG: record.fatG,
+      grams: record.grams,
+      count: record.count,
+      components: record.components,
+      // Stamped here, not by callers: this is what the cross-device merge
+      // orders by, so it must be set on every write without exception.
+      editedAt: DateTime.now().toIso8601String(),
+    );
+    await _writeManualBank(bank);
+  }
+
+  /// Returns the hand-curated bank, for the sync layer.
+  Future<Map<String, FoodBankRecord>> readManualBank() => _readManualBank();
+
+  /// Replaces the hand-curated bank with a merge result from the sync layer.
+  Future<void> applyMergedManualBank(Map<String, FoodBankRecord> bank) =>
+      _writeManualBank(bank);
+
+  /// All known food records: log-derived entries merged with manually-added
+  /// ones, sorted by count descending.
+  ///
+  /// Log-derived records (from [readBank]) take precedence over manual records
+  /// with the same normalized name.
+  Future<List<FoodBankRecord>> mergedEntries() async {
+    final logBank = await readBank();
+    final manualBank = await _readManualBank();
+    final merged = <String, FoodBankRecord>{...manualBank, ...logBank};
+    return merged.values.toList()..sort((a, b) => b.count.compareTo(a.count));
+  }
+
+  // ---------------------------------------------------------------------------
+  // Search
+  // ---------------------------------------------------------------------------
+
+  /// Returns banked foods matching [query], best match first.
+  ///
+  /// An empty query returns the most-logged foods. Mirrors
+  /// `_foodbank.search_foods`. Searches both log-derived and manually-added
+  /// entries; log-derived entries win on name collision.
+  Future<List<FoodSuggestion>> search(
+    String query, {
+    int limit = defaultSuggestions,
+  }) async {
+    final logBank = await readBank();
+    final manualBank = await _readManualBank();
+    final bank = <String, FoodBankRecord>{...manualBank, ...logBank};
+    final normalized = _normalize(query);
+    if (normalized.isEmpty) return _rankedAll(bank, limit);
+
+    final scored = <(double score, double count, FoodSuggestion suggestion)>[];
+    for (final mapEntry in bank.entries) {
+      final score = matchScore(normalized, mapEntry.key);
+      if (score < fuzzyThreshold) continue;
+      final record = mapEntry.value;
+      scored.add((
+        score,
+        record.count,
+        FoodSuggestion(
+          name: _displayName(record, mapEntry.key),
+          nutrition: _recordToNutrition(record),
+        ),
+      ));
+    }
+    scored.sort((a, b) {
+      final byScore = b.$1.compareTo(a.$1);
+      return byScore != 0 ? byScore : b.$2.compareTo(a.$2);
+    });
+    return scored.take(limit).map((s) => s.$3).toList();
+  }
+
+  List<FoodSuggestion> _rankedAll(
+    Map<String, FoodBankRecord> bank,
+    int limit,
+  ) {
+    final ranked = bank.entries.toList()
+      ..sort((a, b) => b.value.count.compareTo(a.value.count));
+    return ranked
+        .take(limit)
+        .map(
+          (mapEntry) => FoodSuggestion(
+            name: _displayName(mapEntry.value, mapEntry.key),
+            nutrition: _recordToNutrition(mapEntry.value),
+          ),
+        )
+        .toList();
+  }
+}
diff --git a/app/pubspec.yaml b/app/pubspec.yaml
index 085d7b4..261a7e0 100644
--- a/app/pubspec.yaml
+++ b/app/pubspec.yaml
@@ -2,7 +2,7 @@ name: diet_guard_app
 description: "Companion phone app for diet_guard: log meals on the go."
 publish_to: 'none'
 
-version: 1.0.26+1
+version: 1.0.27+1
 
 environment:
   sdk: ^3.12.2
diff --git a/app/test/firebase_backend_google_test.dart b/app/test/firebase_backend_google_test.dart
index 7ba859d..ca018b3 100644
--- a/app/test/firebase_backend_google_test.dart
+++ b/app/test/firebase_backend_google_test.dart
@@ -1,11 +1,11 @@
 import 'dart:convert';
 
 import 'package:crdt_sync/crdt_sync.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
+import 'package:diet_guard_app/services/google_sign_in_backend.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:http/http.dart' as http;
 import 'package:http/testing.dart' as http_testing;
-import 'package:diet_guard_app/services/firebase_backend.dart';
-import 'package:diet_guard_app/services/google_sign_in_backend.dart';
 
 import 'fake_secure_storage.dart';
 
diff --git a/app/test/services/sync_state_factory_test.dart b/app/test/services/sync_state_factory_test.dart
index 7600947..2c625ca 100644
--- a/app/test/services/sync_state_factory_test.dart
+++ b/app/test/services/sync_state_factory_test.dart
@@ -10,7 +10,7 @@ library;
 import 'dart:io';
 
 import 'package:crdt_sync/crdt_sync.dart';
-import 'package:diet_guard_app/services/firebase_backend.dart';
+import 'package:diet_guard_app/services/firebase_client.dart';
 import 'package:diet_guard_app/services/sync_state_factory_io.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:path/path.dart' as p;