Remove the _lastActivityRecreation field and the onAppOpened(...) method from LiveActivityService, which previously handled ending/creating activities, refreshing push tokens, fetching the week's timetable and scheduling background fetch. Update home_screen to call LiveActivityService.checkAndUpdateTimetable(...) instead of onAppOpened, and tweak related log messages to clarify the behavior. This simplifies LiveActivity lifecycle on app resume and stops forced activity recreation/token refresh performed by the removed method.
Multiple fixes and improvements for watch <> phone sync, token recovery, and live activity behavior:
- WatchSessionManager: add mergeApplicationContext to avoid clobbering app context, add thread-safe pending auth queue and flush, add sendMessageToWatch API, ensure message handling runs on main thread, add reply-timeout logic for language requests, support fire-and-forget messages, and improve enqueue/flush logic.
- WatchConnectivityManager & SettingsView: publish shared session state on force-logout/logout and improve account-switch/token handling; clear DataStore error and reset recovery state after token updates.
- DataStore & WatchL10n: add recovery-in-progress guard to avoid duplicate recovery runs, reset language version tracking on account switch, make WatchL10n.setLanguage main-thread safe.
- TokenManager & SharedKeychainManager: remove old keychain observer plumbing and instead publish shared session state when active token changes or is deleted.
- UI tweaks: reduce icon/text sizes and spacing in pairing view; only show sync button when paired; Settings logout now also publishes shared state.
- Watch sync wiring in Flutter: replace direct watch_connectivity usage with a MethodChannel-backed WatchSyncHelper.sendMessageToWatch and onWatchMessage callback; main and pairing UI updated accordingly.
- Kreta client: replace simple boolean mutex with a Completer-based mutex and timeout handling to avoid busy-waiting.
- LiveActivityService: throttle/avoid frequent activity recreation (cache last recreation time), skip placeholder creation when called from background, and minor cache-clearing adjustments.
- HomeScreen: add WidgetsBindingObserver to manage lifecycle, prevent prefetch while backgrounded, debounce prefetch, ensure LiveActivity registration runs once and refresh on resume after first prefetch.
These changes increase robustness of token sync and account switching, reduce race conditions and duplicate work, and avoid conflicts between WCSession and Flutter plugin delegates.
