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/auth/repository.go

@@ -4,13 +4,12 @@
 package auth
 
 import (
+	"Wavelet/core"
+	"Wavelet/core/contracts"
 	"context"
 	"sync"
 
 	"gorm.io/gorm"
-
-	"Wavelet/core"
-	"Wavelet/core/contracts"
 )
 
 var (
@@ -120,6 +119,6 @@ func ListExternalAccountsByUserID(ctx context.Context, userID uint64) ([]Externa
 }
 
 // UnbindExternalAccount 解绑外部账号
-func UnbindExternalAccount(ctx context.Context, id uint64, userID uint64) error {
+func UnbindExternalAccount(ctx context.Context, id, userID uint64) error {
 	return getDB(ctx).Where("id = ? AND user_id = ?", id, userID).Delete(&ExternalAccount{}).Error
 }