fix: reduce emby load and stabilize strm scan

internal/database/database.go

@@ -75,7 +75,28 @@ func AutoMigrate(db *gorm.DB) error {
 	if err := db.AutoMigrate(model.AllModels()...); err != nil {
 		return err
 	}
-	return enforceTelegramBindingOneToOne(db)
+	if err := enforceTelegramBindingOneToOne(db); err != nil {
+		return err
+	}
+	return ensurePerformanceIndexes(db)
+}
+
+func ensurePerformanceIndexes(db *gorm.DB) error {
+	statements := []string{
+		`CREATE INDEX IF NOT EXISTS idx_media_library_created_active ON media(library_id, created_at DESC) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_media_library_episode_active ON media(library_id, season_num, episode_num, created_at DESC) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_media_series_active ON media(series_id, season_num, episode_num) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_favorites_user_media_active ON favorites(user_id, media_id) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_playback_histories_user_media_active ON playback_histories(user_id, media_id, watched_at DESC) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_playback_histories_resume_active ON playback_histories(user_id, completed, watched_at DESC) WHERE deleted_at IS NULL`,
+		`CREATE INDEX IF NOT EXISTS idx_play_profiles_user_created_active ON play_profiles(user_id, created_at DESC) WHERE deleted_at IS NULL`,
+	}
+	for _, stmt := range statements {
+		if err := db.Exec(stmt).Error; err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func enforceTelegramBindingOneToOne(db *gorm.DB) error {

internal/database/database_test.go

@@ -45,3 +45,31 @@ func TestEnforceTelegramBindingOneToOneCleansDuplicatesAndAddsIndex(t *testing.T
 		t.Fatal("expected unique index to reject another active binding for the same user")
 	}
 }
+
+func TestEnsurePerformanceIndexesCreatesHotPathIndexes(t *testing.T) {
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(&model.Media{}, &model.Favorite{}, &model.PlaybackHistory{}, &model.PlayProfile{}); err != nil {
+		t.Fatal(err)
+	}
+	if err := ensurePerformanceIndexes(db); err != nil {
+		t.Fatal(err)
+	}
+	for _, name := range []string{
+		"idx_media_library_created_active",
+		"idx_media_library_episode_active",
+		"idx_favorites_user_media_active",
+		"idx_playback_histories_user_media_active",
+		"idx_play_profiles_user_created_active",
+	} {
+		var count int
+		if err := db.Raw(`SELECT COUNT(1) FROM sqlite_master WHERE type = 'index' AND name = ?`, name).Scan(&count).Error; err != nil {
+			t.Fatal(err)
+		}
+		if count != 1 {
+			t.Fatalf("index %s count = %d, want 1", name, count)
+		}
+	}
+}