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/enrich.go

@@ -2,6 +2,7 @@ package ai
 
 import (
 	"context"
+	"encoding/json"
 	"time"
 
 	"git.pengzhan.dev/haopengzhan/rsspipe/internal/ai"
@@ -12,7 +13,35 @@ import (
 )
 
 // LoadConfig fetches current AI provider configuration from system settings.
-func LoadConfig(database *db.DB) ai.Config {
+func LoadConfig(database *db.DB) (ai.Config, []models.PromptTemplate) {
+	raw, err := database.GetSetting("ai_settings")
+	if err == nil && raw != "" {
+		var s models.AISettings
+		if err := json.Unmarshal([]byte(raw), &s); err == nil {
+			provider := s.Provider
+			if provider == "" {
+				provider = "openai"
+			}
+			baseURL := s.BaseURL
+			if baseURL == "" {
+				baseURL = "https://api.openai.com/v1"
+			}
+			model := s.Model
+			if model == "" {
+				model = "gpt-4o-mini"
+			}
+			return ai.Config{
+				Enabled:     s.Enabled,
+				Provider:    provider,
+				BaseURL:     baseURL,
+				APIKey:      s.APIKey,
+				Model:       model,
+				Temperature: s.Temperature,
+				MaxTokens:   s.MaxTokens,
+			}, s.Prompts
+		}
+	}
+
 	settings, _ := database.GetSettingsMap()
 	enabled := settings["ai_enabled"] == "true" || settings["ai_enabled"] == "1"
 	provider := settings["ai_provider"]
@@ -33,13 +62,19 @@ func LoadConfig(database *db.DB) ai.Config {
 		BaseURL:  baseURL,
 		APIKey:   settings["ai_api_key"],
 		Model:    model,
-	}
+	}, nil
 }
 
 // NewEnrichmentHandler creates a worker action handler for AI variant enrichment.
 func NewEnrichmentHandler(database *db.DB, client *ai.Client, log *zap.Logger) worker.ActionHandler {
 	return func(ctx context.Context, entry models.FeedEntry, params map[string]interface{}) (*worker.ActionResult, error) {
-		cfg := LoadConfig(database)
+		cfg, prompts := LoadConfig(database)
+		if !cfg.Enabled {
+			log.Warn("AI action 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 action skipped: API key is not configured in Settings > AI & Integrations",
 				zap.String("entry_id", entry.ID),
@@ -52,6 +87,17 @@ func NewEnrichmentHandler(database *db.DB, client *ai.Client, log *zap.Logger) w
 		if prompt == "" {
 			prompt, _ = params["custom_prompt"].(string)
 		}
+		if prompt == "" {
+			for _, p := range prompts {
+				if p.IsDefault {
+					prompt = p.Prompt
+					break
+				}
+			}
+			if prompt == "" && len(prompts) > 0 {
+				prompt = prompts[0].Prompt
+			}
+		}
 		vKey, _ := params["variant_key"].(string)
 		if vKey == "" {
 			vKey = "ai_summary"

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),