feat: sync log, cache clear endpoint, Todoist projects from cached tasks

- migration 016: sync_log table
- store: AddSyncLogEntry, GetRecentSyncLog, InvalidateAllCaches, GetProjectsFromTasks
- settings: HandleClearCache (POST /settings/clear-cache), SyncLog in page data
- settings: use GetProjectsFromTasks instead of deprecated Todoist REST /projects
- handlers: populate atom projects from store
- agent: log warning on registration failure instead of silently swallowing
- google_tasks: simplify URL literal
- tests: sync log CRUD, clear cache handler, settings page includes sync log,
  sync sources adds log entry, incremental sync paths, task completion
  response/headers, calendar cache fallback

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/internal/store/sqlite.go b/internal/store/sqlite.go
index 158febc..366b24e 100644
--- a/internal/store/sqlite.go
+++ b/internal/store/sqlite.go
@@ -1397,6 +1397,37 @@ func (s *Store) SyncSourceConfigs(source, itemType string, items []models.Source
 	return tx.Commit()
 }
 
+// InvalidateAllCaches removes cache metadata for all known cache keys
+func (s *Store) InvalidateAllCaches() error {
+	_, err := s.db.Exec(`DELETE FROM cache_metadata WHERE key IN (?, ?, ?, ?)`,
+		CacheKeyTodoistTasks, CacheKeyTrelloBoards, CacheKeyPlanToEatMeals, CacheKeyGoogleCalendar)
+	return err
+}
+
+// GetProjectsFromTasks returns distinct projects from the tasks table
+func (s *Store) GetProjectsFromTasks() ([]models.Project, error) {
+	rows, err := s.db.Query(`
+		SELECT DISTINCT project_id, project_name
+		FROM tasks
+		WHERE project_id != ''
+		ORDER BY project_name
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+
+	var projects []models.Project
+	for rows.Next() {
+		var p models.Project
+		if err := rows.Scan(&p.ID, &p.Name); err != nil {
+			return nil, err
+		}
+		projects = append(projects, p)
+	}
+	return projects, rows.Err()
+}
+
 // Feature toggles
 
 // GetFeatureToggles returns all feature toggles
@@ -1457,3 +1488,42 @@ func (s *Store) DeleteFeatureToggle(name string) error {
 	_, err := s.db.Exec(`DELETE FROM feature_toggles WHERE name = ?`, name)
 	return err
 }
+
+// SyncLogEntry represents a single entry in the sync activity log
+type SyncLogEntry struct {
+	ID        int64
+	EventType string
+	Message   string
+	CreatedAt time.Time
+}
+
+// AddSyncLogEntry records a sync or cache event in the log
+func (s *Store) AddSyncLogEntry(eventType, message string) error {
+	_, err := s.db.Exec(
+		`INSERT INTO sync_log (event_type, message) VALUES (?, ?)`,
+		eventType, message,
+	)
+	return err
+}
+
+// GetRecentSyncLog returns the most recent sync log entries, newest first
+func (s *Store) GetRecentSyncLog(limit int) ([]SyncLogEntry, error) {
+	rows, err := s.db.Query(
+		`SELECT id, event_type, message, created_at FROM sync_log ORDER BY id DESC LIMIT ?`,
+		limit,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+
+	var entries []SyncLogEntry
+	for rows.Next() {
+		var e SyncLogEntry
+		if err := rows.Scan(&e.ID, &e.EventType, &e.Message, &e.CreatedAt); err != nil {
+			return nil, err
+		}
+		entries = append(entries, e)
+	}
+	return entries, rows.Err()
+}