chore(lint): unify formatting on golangci-lint fmt (gofumpt), uncap issue reporting, fix gofumpt drift

- make format 现在与 code-check 使用同一格式化器（golangci-lint fmt），消除 goimports -local 与 gofumpt 的格式拉锯
- .golangci.yml 关闭默认 50/3 截断，完整上报所有问题（只增强不弱化）
- 全库 gofumpt 规范化（203 files, 纯格式无行为变更）

backend/plugins/domain/upload/stats/category.go

@@ -5,9 +5,8 @@
 package stats
 
 import (
-	"strings"
-
 	"Wavelet/plugins/domain/upload/util"
+	"strings"
 )
 
 const (

backend/plugins/domain/upload/stats/stats_counter.go

@@ -4,15 +4,14 @@
 package stats
 
 import (
+	"Wavelet/pkg/logger"
+	"Wavelet/plugins/domain/upload/models"
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"time"
 
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
-
-	"Wavelet/pkg/logger"
-	"Wavelet/plugins/domain/upload/models"
-	"Wavelet/plugins/domain/upload/shared"
 )
 
 // ApplyUploadStatsAdd increments incremental stats for a newly active upload record.

backend/plugins/domain/upload/stats/stats_counter_test.go

@@ -4,15 +4,14 @@
 package stats
 
 import (
+	"Wavelet/pkg/testhelper"
+	"Wavelet/plugins/domain/upload/models"
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"testing"
 	"time"
 
 	"gorm.io/gorm"
-
-	"Wavelet/pkg/testhelper"
-	"Wavelet/plugins/domain/upload/models"
-	"Wavelet/plugins/domain/upload/shared"
 )
 
 type mockDBService struct {