billsplit: fix the two CI gates that were already red on main

flutter analyze --fatal-infos exited 1 at 6713ef3 with four
unnecessary_unawaited issues in lib/ui/home_screen.dart: Flutter now
annotates Navigator.push with @awaitNotRequired, which makes the
unawaited() wrappers redundant. Removed all four wrappers and the
dart:async import they were the only user of.

dart format --set-exit-if-changed was separately red on three test files
left unformatted by a68313f. One trailing blank line each.

Both are steps in .github/workflows/billsplit-ci.yml, so billsplit CI was
failing on main for reasons unrelated to any current work. Fixing them
first means the platform-directory deletion that follows can be verified
green-to-green.

flutter test: 60 passing before and after - the unchanged count is what
proves the unawaited() removals did not shift navigation timing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011w2Pj4Ek3ZNMQVYcFHgXDY

billsplit/lib/ui/home_screen.dart

@@ -1,4 +1,3 @@
-import 'dart:async';
 import 'dart:convert';
 
 import 'package:billsplit/domain/eparagon_parser.dart';
@@ -26,11 +25,9 @@ class HomeScreen extends StatelessWidget {
           IconButton(
             tooltip: 'People & groups',
             icon: const Icon(Icons.group),
-            onPressed: () => unawaited(
-              Navigator.push(
-                context,
-                MaterialPageRoute<void>(builder: (_) => const PeopleScreen()),
-              ),
+            onPressed: () => Navigator.push(
+              context,
+              MaterialPageRoute<void>(builder: (_) => const PeopleScreen()),
             ),
           ),
         ],
@@ -70,12 +67,10 @@ class HomeScreen extends StatelessWidget {
                           formatPln(r.itemsTotalGr),
                           style: Theme.of(context).textTheme.titleMedium,
                         ),
-                        onTap: () => unawaited(
-                          Navigator.push(
-                            context,
-                            MaterialPageRoute<void>(
-                              builder: (_) => ReceiptScreen(receiptId: r.id),
-                            ),
+                        onTap: () => Navigator.push(
+                          context,
+                          MaterialPageRoute<void>(
+                            builder: (_) => ReceiptScreen(receiptId: r.id),
                           ),
                         ),
                       ),
@@ -146,11 +141,9 @@ class HomeScreen extends StatelessWidget {
       for (final w in result.warnings) {
         messenger.showSnackBar(SnackBar(content: Text(w)));
       }
-      unawaited(
-        nav.push(
-          MaterialPageRoute<void>(
-            builder: (_) => ReceiptScreen(receiptId: result.receipt.id),
-          ),
+      nav.push(
+        MaterialPageRoute<void>(
+          builder: (_) => ReceiptScreen(receiptId: result.receipt.id),
         ),
       );
     } on EParagonParseException catch (e) {
@@ -189,11 +182,9 @@ class HomeScreen extends StatelessWidget {
     if (title == null || title.trim().isEmpty) return;
     final r = Receipt(id: Ids.next(), title: title.trim());
     state.addReceipt(r);
-    unawaited(
-      nav.push(
-        MaterialPageRoute<void>(
-          builder: (_) => ReceiptScreen(receiptId: r.id),
-        ),
+    nav.push(
+      MaterialPageRoute<void>(
+        builder: (_) => ReceiptScreen(receiptId: r.id),
       ),
     );
   }

billsplit/test/people_flows_test.dart

@@ -1,6 +1,5 @@
 // People screen flows.
 
-
 import 'package:billsplit/domain/models.dart';
 import 'package:billsplit/state/app_state.dart';
 import 'package:billsplit/ui/people_screen.dart';

billsplit/test/receipt_flows_test.dart

@@ -1,6 +1,5 @@
 // Receipt screen flows.
 
-
 import 'package:billsplit/domain/models.dart';
 import 'package:billsplit/state/app_state.dart';
 import 'package:billsplit/ui/receipt_screen.dart';

billsplit/test/receipt_items_test.dart

@@ -2,7 +2,6 @@
 
 // Receipt screen flows.
 
-
 import 'package:billsplit/domain/models.dart';
 import 'package:billsplit/state/app_state.dart';
 import 'package:billsplit/ui/receipt_screen.dart';

docs/superpowers/contracts/billsplit-ci-green-2026-08-17.json

@@ -0,0 +1,17 @@
+{
+  "title": "Make the billsplit CI gates green before touching billsplit",
+  "objective": "billsplit CI was already failing on main at 6713ef3: flutter analyze --fatal-infos exited 1 with four unnecessary_unawaited issues, and dart format --set-exit-if-changed exited 1 on three test files left unformatted by an earlier split commit. Both are steps in .github/workflows/billsplit-ci.yml. This change fixes exactly those two gates and nothing else, so that the platform-directory deletion that follows can be verified as green-to-green rather than red-to-red.",
+  "acceptance_criteria": [
+    "flutter analyze --fatal-infos exits 0 in billsplit/ (was exit 1, 4 issues)",
+    "dart format --set-exit-if-changed . exits 0 in billsplit/ (was exit 1, 3 changed files)",
+    "flutter test still reports exactly 60 passing tests, the same count as at HEAD - proving the unawaited() removals did not alter navigation behaviour in the widget tests",
+    "No lint suppression, no analysis_options exclusion, and no lowered threshold is used to reach any of the above"
+  ],
+  "out_of_scope": [
+    "Deleting billsplit/windows, macos, ios or linux - that is the next commit, with its own contract",
+    "Any change to billsplit behaviour, UI, or test assertions",
+    "Reformatting Dart files outside billsplit/",
+    "The 45 bucket_catch eslint errors and the usage_report split work, both tracked separately in this session"
+  ],
+  "verifier": "cd billsplit && flutter analyze --fatal-infos && dart format --set-exit-if-changed . && flutter test - the first three steps of .github/workflows/billsplit-ci.yml. Each was run before and after the change and the exit codes are recorded in docs/superpowers/evidence/billsplit-ci-green-2026-08-17.json."
+}

docs/superpowers/evidence/billsplit-ci-green-2026-08-17.json

@@ -0,0 +1,38 @@
+{
+  "intent": "Restore the two billsplit CI gates that were already failing on main, so that subsequent billsplit changes can be verified against a green baseline instead of a red one.",
+  "scope": [
+    "billsplit/lib/ui/home_screen.dart - remove redundant unawaited() wrappers and the now-unused dart:async import",
+    "billsplit/test/people_flows_test.dart, receipt_flows_test.dart, receipt_items_test.dart - apply dart format (one trailing blank line each)",
+    "Non-goal: no behaviour change, no test added or removed, no platform-directory work (that is a separate commit)"
+  ],
+  "changes": [
+    "Removed four unawaited(...) wrappers around Navigator.push / nav.push at home_screen.dart lines 29, 73, 149, 192. Flutter now annotates Navigator.push with @awaitNotRequired, which makes the wrapper redundant and triggers the unnecessary_unawaited lint. Each removal is a pure unwrapping of the argument expression; no await was introduced and no control flow changed.",
+    "Removed 'import dart:async' from home_screen.dart, which was only present for unawaited(). Future is exported by dart:core, so the three async methods in the file still analyze clean.",
+    "Ran dart format on three test files left unformatted by commit a68313f (Split every over-cap billsplit Dart file). Each change is the deletion of a single trailing blank line."
+  ],
+  "verification": [
+    {
+      "command": "flutter analyze --fatal-infos (in billsplit/)",
+      "result": "pass",
+      "evidence": "Before this change, at HEAD 6713ef3: exit 1, '4 issues found', all four unnecessary_unawaited in lib/ui/home_screen.dart at 29:30, 73:38, 149:7, 192:5. After: exit 0, 'No issues found! (ran in 2.1s)'. This is the exact command .github/workflows/billsplit-ci.yml runs."
+    },
+    {
+      "command": "dart format --set-exit-if-changed . (in billsplit/)",
+      "result": "pass",
+      "evidence": "Before: 'Formatted 29 files (3 changed)' - people_flows_test.dart, receipt_flows_test.dart, receipt_items_test.dart were unformatted at HEAD. After: 'Formatted 29 files (0 changed)', exit 0. This is also a billsplit-ci.yml step."
+    },
+    {
+      "command": "flutter test (in billsplit/)",
+      "result": "pass",
+      "evidence": "60 tests passed both before and after the change. The unchanged count is the discriminating check: removing unawaited() could have altered navigation timing in the widget tests, and did not."
+    }
+  ],
+  "risks": [
+    "unawaited() communicates intent to a human reader as well as to the analyzer. Removing it makes the fire-and-forget nature of these navigation calls implicit rather than explicit. Accepted because the @awaitNotRequired annotation on Navigator.push now carries that same information at the API level, and the alternative is a permanently red --fatal-infos gate or a lint suppression.",
+    "The three formatting-only test edits touch files this task did not otherwise need to change. They are included because dart format runs repo-wide in CI, so the gate cannot be made green without them."
+  ],
+  "rollback": [
+    "git revert the commit. home_screen.dart returns to using unawaited() with the dart:async import, and the three test files regain their trailing blank lines.",
+    "After rollback, expect flutter analyze --fatal-infos to exit 1 with 4 unnecessary_unawaited issues and dart format --set-exit-if-changed to exit 1 with 3 changed files - i.e. billsplit CI red again, as it was at 6713ef3. flutter test should still report 60 passing."
+  ]
+}