feat: 配置列表分页与钉钉机器人分钟级排队限流

统一 sources/templates/channels/rules 列表为分页响应，避免配置增多时全量返回；按钉钉 access_token 限制每分钟发送并在超限时等待下一分钟，降低触发官方封禁风险。

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/store/source.go

@@ -54,13 +54,19 @@ func (s *Store) GetSourceByName(ctx context.Context, name string) (*model.Source
 	return &src, nil
 }
 
-func (s *Store) ListSources(ctx context.Context) ([]model.Source, error) {
-	sources := make([]model.Source, 0)
-	err := s.DB.SelectContext(ctx, &sources, `SELECT * FROM notification_source ORDER BY id`)
-	if err != nil {
-		return nil, fmt.Errorf("list sources: %w", err)
+func (s *Store) ListSources(ctx context.Context, page PageFilter) ([]model.Source, int, error) {
+	var count int
+	if err := s.DB.GetContext(ctx, &count, `SELECT COUNT(*) FROM notification_source`); err != nil {
+		return nil, 0, fmt.Errorf("count sources: %w", err)
 	}
-	return sources, nil
+
+	page.Normalize()
+	sources := make([]model.Source, 0)
+	err := s.DB.SelectContext(ctx, &sources, `SELECT * FROM notification_source ORDER BY id LIMIT ? OFFSET ?`, page.PageSize, page.Offset())
+	if err != nil {
+		return nil, 0, fmt.Errorf("list sources: %w", err)
+	}
+	return sources, count, nil
 }
 
 func (s *Store) UpdateSource(ctx context.Context, id int, src *model.Source) error {