Flutter's Linux embedder manages ~20fps at 3840x2160 -- measured on a stock
`flutter create` counter app, so it is the toolkit rather than this code --
where the same Dart rendered by Chrome sustains ~144fps (evidence in
~/todo/docs/desktop-performance-findings.md). The desktop target therefore
becomes a Flutter *web* build; Android is untouched.
`dart:io` does not fail a web *compile* -- it resolves to a stub that throws
at runtime -- so every platform edge moves behind a conditional export rather
than being discovered later as a blank white window:
- storage: `document_store*.dart`, files on Android and IndexedDB in the
browser (mirrored to the desktop wrapper, which is what makes a wiped
Chrome profile recoverable). Document names stay the exact pre-web
filenames so an installed phone keeps reading its existing log.
- photos: `blob_store*.dart` plus `attached_image*.dart`, since `Image.file`
cannot resolve an IndexedDB key. The picker itself has web support; what
changed is the storage and display model. Camera *capture* is genuinely
lost on desktop -- and photos never crossed devices anyway, `imagePath`
being stripped before push.
- scheduling: `background_tasks*.dart`. A browser has no WorkManager
equivalent -- a closed tab runs nothing -- so the desktop runs an in-page
5-minute check while its window is open. That loses nothing on the PC,
where `diet-guard-gate.timer` already locks the screen on an unlogged
slot, which is strictly stronger than a notification.
- notifications: `notification_backend*.dart`, the browser Notifications API
in place of flutter_local_notifications.
- the GitHub token: `token_vault*.dart`. On web it is *not* held by the
browser at all -- flutter_secure_storage's web backend is WebCrypto-wrapped
localStorage with the wrap key beside the ciphertext, which is obfuscation,
not encryption at rest -- so the desktop wrapper owns it and proxies the
API (`github_client_factory*.dart`).
`Platform.isAndroid` itself throws on web, so every platform branch now tests
`kIsWeb` first; the battery-optimization row (permission_handler, no web
implementation) is hidden off Android.
The desktop pushes under device id `desktop`, not `phone`: sharing an id
would have made the two devices overwrite each other's pushed log on every
tick. The Python side enumerates device directories generically, so it needs
no change.
Tests move onto the same seams -- the file-backed stores keep the atomicity
and unreadable-file guarantees where they belong.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
