refactor(backend): apply go fix updates for Go 1.26

backend/go.mod

@@ -1,6 +1,6 @@
 module github.com/0x2E/fusion
 
-go 1.25
+go 1.26
 
 require (
 	github.com/0x2E/feedfinder v0.1.1

backend/internal/handler/handler.go

@@ -217,10 +217,10 @@ func (h *Handler) authMiddleware() gin.HandlerFunc {
 	}
 }
 
-func dataResponse(c *gin.Context, data interface{}) {
+func dataResponse(c *gin.Context, data any) {
 	c.JSON(200, gin.H{"data": data})
 }
 
-func listResponse(c *gin.Context, data interface{}, total int) {
+func listResponse(c *gin.Context, data any, total int) {
 	c.JSON(200, gin.H{"data": data, "total": total})
 }

backend/internal/handler/item_test.go

@@ -17,7 +17,7 @@ func TestMarkItemsBatchValidation(t *testing.T) {
 		name    string
 		path    string
 		handler gin.HandlerFunc
-		body    interface{}
+		body    any
 	}{
 		{name: "read rejects too many ids", path: "/api/items/-/read", handler: (&Handler{}).markItemsRead, body: gin.H{"ids": ids}},
 		{name: "unread rejects empty ids", path: "/api/items/-/unread", handler: (&Handler{}).markItemsUnread, body: gin.H{"ids": []int64{}}},

backend/internal/handler/test_helpers_test.go

@@ -16,7 +16,7 @@ func newTestRouter() *gin.Engine {
 	return gin.New()
 }
 
-func mustJSONBody(t *testing.T, payload interface{}) *bytes.Reader {
+func mustJSONBody(t *testing.T, payload any) *bytes.Reader {
 	t.Helper()
 
 	body, err := json.Marshal(payload)

backend/internal/pullpolicy/schedule.go

@@ -156,7 +156,7 @@ func parseCacheControlMaxAgeSeconds(cacheControl string) int64 {
 		return 0
 	}
 
-	for _, part := range strings.Split(cacheControl, ",") {
+	for part := range strings.SplitSeq(cacheControl, ",") {
 		token := strings.TrimSpace(strings.ToLower(part))
 		if !strings.HasPrefix(token, "max-age=") {
 			continue

backend/internal/store/bookmark.go

@@ -14,7 +14,7 @@ func (s *Store) ListBookmarks(limit, offset int) ([]*model.Bookmark, error) {
 		FROM bookmarks
 		ORDER BY created_at DESC, id DESC
 	`
-	args := []interface{}{}
+	args := []any{}
 
 	if limit > 0 {
 		query += ` LIMIT :limit`

backend/internal/store/feed.go

@@ -198,7 +198,7 @@ type UpdateFeedParams struct {
 // UpdateFeed performs partial update of feed fields using a single dynamic UPDATE query.
 func (s *Store) UpdateFeed(id int64, params UpdateFeedParams) error {
 	setClauses := []string{}
-	args := []interface{}{sql.Named("id", id)}
+	args := []any{sql.Named("id", id)}
 
 	if params.GroupID != nil {
 		setClauses = append(setClauses, "group_id = :group_id")

backend/internal/store/item.go

@@ -28,7 +28,7 @@ func (s *Store) ListItems(params ListItemsParams) ([]*model.Item, error) {
 		SELECT items.id, items.feed_id, items.guid, items.title, items.link, items.content, items.pub_date, items.unread, items.created_at
 		FROM items
 	`
-	args := []interface{}{}
+	args := []any{}
 
 	// Join feeds table if filtering by GroupID
 	if params.GroupID != nil {
@@ -208,10 +208,7 @@ func (s *Store) BatchUpdateItemsUnread(ids []int64, unread bool) error {
 
 	const chunkSize = 500
 	for start := 0; start < len(ids); start += chunkSize {
-		end := start + chunkSize
-		if end > len(ids) {
-			end = len(ids)
-		}
+		end := min(start+chunkSize, len(ids))
 
 		if err := s.batchUpdateItemsUnreadChunk(ids[start:end], unread); err != nil {
 			return err
@@ -227,7 +224,7 @@ func (s *Store) batchUpdateItemsUnreadChunk(ids []int64, unread bool) error {
 	}
 
 	placeholders := make([]string, len(ids))
-	args := make([]interface{}, 0, len(ids)+1)
+	args := make([]any, 0, len(ids)+1)
 	args = append(args, sql.Named("unread", boolToInt(unread)))
 	for i, id := range ids {
 		paramName := fmt.Sprintf("id%d", i)
@@ -341,7 +338,7 @@ func (s *Store) searchItemsLike(query string, limit int) ([]*SearchItemResult, e
 // CountItems returns the total count of items matching the filter criteria.
 func (s *Store) CountItems(params ListItemsParams) (int, error) {
 	query := `SELECT COUNT(*) FROM items`
-	args := []interface{}{}
+	args := []any{}
 
 	if params.GroupID != nil {
 		query += ` INNER JOIN feeds ON items.feed_id = feeds.id`

backend/internal/store/item_test.go

@@ -345,7 +345,7 @@ func TestBatchUpdateItemsUnreadChunked(t *testing.T) {
 	feed := mustCreateFeed(t, store, group.ID, "Chunk Feed", "https://example.com/chunk-feed", "https://example.com", "")
 
 	inputs := make([]BatchCreateItemInput, 0, 520)
-	for i := 0; i < 520; i++ {
+	for i := range 520 {
 		inputs = append(inputs, BatchCreateItemInput{
 			GUID:    fmt.Sprintf("chunk-guid-%d", i),
 			Title:   "Chunk Item",