refactor: upgrade to Go 1.26 and modernize code idioms

- Replace `interface{}` with `any` type alias across all packages
- Use built-in `min()`/`max()` for parameter clamping
- Use `slices.SortFunc`, `slices.Min`, `slices.Max` for cleaner code
- Use `strings.Cut()` for simpler string parsing in auth middleware
- Use `errors.Is()` for proper error comparison in handlers
- Update dependencies: golang.org/x/image 0.37.0 -> 0.38.0
- Add Wire code generation guidelines to ARCHITECTURE.md
- Disable Go cache in CI build workflow

internal/service/admin_dashboard_service.go

@@ -173,12 +173,7 @@ func (s *adminDashboardServiceImpl) GetStats(ctx context.Context) (*dto.Dashboar
 
 // GetUserActivityTrend 获取用户活跃度趋势
 func (s *adminDashboardServiceImpl) GetUserActivityTrend(ctx context.Context, days int) ([]dto.UserActivityTrendResponse, error) {
-	if days <= 0 {
-		days = 7
-	}
-	if days > 30 {
-		days = 30
-	}
+	days = min(max(days, 1), 30)
 
 	now := time.Now()
 	results := make([]dto.UserActivityTrendResponse, days)
@@ -282,12 +277,7 @@ func (s *adminDashboardServiceImpl) GetContentStats(ctx context.Context) (*dto.C
 
 // GetPendingContent 获取待审核内容
 func (s *adminDashboardServiceImpl) GetPendingContent(ctx context.Context, limit int) ([]dto.PendingContentResponse, error) {
-	if limit <= 0 {
-		limit = 10
-	}
-	if limit > 50 {
-		limit = 50
-	}
+	limit = min(max(limit, 1), 50)
 
 	results := make([]dto.PendingContentResponse, 0)