Fix sync worker stall on persistent errors

[Left024]

Credits

This change was made by DeepSeek V4 Pro and has been manually tested by @Left024 on device — verified working correctly.

Problem

When background sync encounters an error (e.g., FreshRSS credentials expire, network issues), the SyncWorker enters infinite exponential backoff (capped at 5h). Users experience this as "auto-refresh stopped working completely" — it never recovers until manual refresh or app restart.

Additional issues:

• After switching accounts, periodic task carries the old accountId but dispatches via "current account" type, causing permanent type-mismatch failure
• ReaderWorker retries indefinitely when any article full-content fetch fails, blocking the entire POST_SYNC_WORK chain (KEEP policy)
• Changes to sync interval / Wi-Fi-only / charging-only settings only update the database but never reschedule the periodic task

Root Cause

1. SyncWorker: sync() returns Result.Retry() → WorkManager exponential backoff. Each retry doubles the wait, permanently suspending the normal sync interval rhythm
2. Account mismatch: enqueuePeriodicWork bakes accountId into inputData, but doWork() uses rssService.get() (current account type) — cross-account dispatch fails with type checks
3. ReaderWorker: any failed article fetch → infinite retry → POST_SYNC_WORK never completes → subsequent syncs can't enqueue new ReaderWorker/WidgetUpdateWorker
4. Settings not applied: sync settings changes only write to DB; rescheduling only happens at app restart via initSync()

Changes

• SyncWorker: capping retries at 3 attempts (1 initial + 2 backoff retries), then returning Result.Failure — for periodic tasks this triggers resetPeriodic(), allowing the next sync interval to proceed normally. Also injecting AccountService to dispatch by inputData.accountId instead of current account
• ReaderWorker: capping retries to avoid blocking POST_SYNC_WORK chain indefinitely; missing full content will be re-fetched by the next sync cycle
• AbstractRssRepository: extracting reschedulePeriodicWork(account) from initSync() for external reuse
• AccountViewModel: calling reschedulePeriodicWork immediately on account switch and sync setting changes, no longer requires app restart
• FeverRssService: changed Result.Failure() to Result.Retry() for behavior consistency with Local/GoogleReader

Additional Improvements (2026-07-22)

Based on testing and further analysis, these incremental changes enhance sync reliability and user experience:

SyncWorker & AbstractRssRepository

• Multi-account initSync: initSync() now iterates all accounts (not just the current one), enqueuing periodic work for each — ensures all accounts get synced after app restart
• Top-level exception guard: doWork() wrapped in try-catch to prevent unhandled exceptions from crashing the worker
• accountId propagation: POST_SYNC_WORK chain passes accountId to ReaderWorker for correct account dispatch
• Expedited one-shot syncs: one-time sync tasks requested with setExpedited() for faster execution
• Schedule extraction: enqueuePeriodicWork schedule constraints extracted into a reusable builder

ReaderWorker

• AccountService injected to resolve account type from inputData.accountId, with fallback to current account for backward compatibility with old tasks
• Full-content fetch retry cap uses its own constant (decoupled from SyncWorker's retry limit)

Network Recovery (AndroidApp.kt)

• Registered NetworkCallback that triggers a one-shot sync when network becomes available after a disconnect — prevents missed sync windows when offline

Battery Optimization (AndroidManifest + ContextExt + TroubleshootingPage)

• Added REQUEST_IGNORE_BATTERY_OPTIMIZATIONS permission to both manifests
• New isIgnoringBatteryOptimizations() and openBatteryOptimizationSettings() extension functions
• Troubleshooting page now displays battery optimization status with a card; fixed crash on invalid nextScheduledMillis (shows "N/A")

Notifications (NotificationHelper.kt)

• Multi-article notifications use InboxStyle to display article title list
• setAutoCancel(true) for automatic dismissal
• Notification IDs use deterministic hash (article.id.hashCode()) instead of random numbers

AccountViewModel

• After account deletion, rebuilds periodic sync for the target account
• Renamed local variable rssService → rssRepo to disambiguate from member property

Strings

• Added battery optimization status strings (Chinese + English)

Files Updated (both commits combined)

• .gitignore
• app/src/googlePlay/AndroidManifest.xml
• app/src/main/AndroidManifest.xml
• app/src/main/java/me/ash/reader/domain/service/AbstractRssRepository.kt
• app/src/main/java/me/ash/reader/domain/service/FeverRssService.kt
• app/src/main/java/me/ash/reader/domain/service/ReaderWorker.kt
• app/src/main/java/me/ash/reader/domain/service/SyncWorker.kt
• app/src/main/java/me/ash/reader/domain/service/WidgetUpdateWorker.kt
• app/src/main/java/me/ash/reader/infrastructure/android/AndroidApp.kt
• app/src/main/java/me/ash/reader/infrastructure/android/NotificationHelper.kt
• app/src/main/java/me/ash/reader/ui/ext/ContextExt.kt
• app/src/main/java/me/ash/reader/ui/page/settings/accounts/AccountViewModel.kt
• app/src/main/java/me/ash/reader/ui/page/settings/troubleshooting/TroubleshootingPage.kt
• app/src/main/res/values-zh-rCN/strings.xml
• app/src/main/res/values/strings.xml