refactor(core): overhaul state transition architecture, persistent job queue, and API layer

- Implement atomic state transitions: add EntryService.PatchEntry() with EntryDiff computation and EventEntryTransition event emission.
- Add persistent SQLite task queue (JobEngine): add jobs table with crash recovery, exponential backoff retries, concurrency control, and idempotency key deduplication.
- Decompose monolithic HTTP handlers: split handlers.go into domain handlers (auth, feeds, entries, jobs, settings, rules, sse).
- Implement real-time Server-Sent Events (/api/events/stream) for multi-tab/device state synchronization.
- Fix SQLite concurrency: apply busy_timeout(10000) and journal_mode(WAL) via DSN query parameters to resolve SQLITE_BUSY (5).
- Fix AI settings & prompt loading: unmarshal JSON from ai_settings, apply configured prompt templates, and enforce strict enabled/API key validations.
- Fix undo share state: remove omitempty from ShareUUID to serialize null for state resets.
- Fix middle list counter: compute true unread/total stats from DB and clean switcher button labels.
- Adapt mobile UI for iOS: add viewport-fit=cover in index.html and calibrate safe-area insets for the bottom navigation and article reader toolbar.
- Add architectural documentation and worklog in docs/009_worklog.md.

internal/actions/ai/triage.go

@@ -15,7 +15,11 @@ import (
 // NewTriageHandler creates a worker action handler for AI autonomous triage decisions.
 func NewTriageHandler(database *db.DB, client *ai.Client, pool *worker.Pool, log *zap.Logger) worker.ActionHandler {
 	return func(ctx context.Context, entry models.FeedEntry, params map[string]interface{}) (*worker.ActionResult, error) {
-		cfg := LoadConfig(database)
+		cfg, _ := LoadConfig(database)
+		if !cfg.Enabled {
+			log.Warn("AI triage skipped: AI features are disabled in Settings", zap.String("entry_id", entry.ID))
+			return nil, nil
+		}
 		if cfg.APIKey == "" && cfg.Provider != "ollama" {
 			log.Warn("AI triage action skipped: API key is not configured in Settings > AI & Integrations",
 				zap.String("entry_id", entry.ID),