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/cache/access_cache.go

@@ -5,13 +5,13 @@
 package cache
 
 import (
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"encoding/json"
 	"strings"
 	"sync"
 	"time"
 
-	"Wavelet/plugins/domain/upload/shared"
 	uploadstorage "Wavelet/plugins/domain/upload/storage"
 )
 

backend/plugins/domain/upload/cache/access_cache_test.go

@@ -4,11 +4,11 @@
 package cache
 
 import (
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"testing"
 	"time"
 
-	"Wavelet/plugins/domain/upload/shared"
 	uploadstorage "Wavelet/plugins/domain/upload/storage"
 )
 

backend/plugins/domain/upload/cache/meta_cache.go

@@ -4,15 +4,14 @@
 package cache
 
 import (
+	"Wavelet/pkg/cache/ram"
+	"Wavelet/plugins/domain/upload/models"
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"fmt"
 	"time"
 
 	"gorm.io/gorm"
-
-	"Wavelet/pkg/cache/ram"
-	"Wavelet/plugins/domain/upload/models"
-	"Wavelet/plugins/domain/upload/shared"
 )
 
 const (
@@ -21,9 +20,7 @@ const (
 	uploadMetaInvalidationChan = "upload:meta_invalidation"
 )
 
-var (
-	uploadMetaRAM = ram.MustNew[uint64, models.Upload](ram.Options{MaximumSize: uploadMetaRAMMaximumSize})
-)
+var uploadMetaRAM = ram.MustNew[uint64, models.Upload](ram.Options{MaximumSize: uploadMetaRAMMaximumSize})
 
 func uploadMetaRedisKey(id uint64) string {
 	return fmt.Sprintf("upload:meta:%d", id)

backend/plugins/domain/upload/cache/meta_cache_test.go

@@ -4,14 +4,13 @@
 package cache
 
 import (
+	"Wavelet/pkg/testhelper"
+	"Wavelet/plugins/domain/upload/models"
+	"Wavelet/plugins/domain/upload/shared"
 	"context"
 	"testing"
 
 	"gorm.io/gorm"
-
-	"Wavelet/pkg/testhelper"
-	"Wavelet/plugins/domain/upload/models"
-	"Wavelet/plugins/domain/upload/shared"
 )
 
 func init() {