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/drivers/driver_inproc_cron/plugin.go

@@ -5,11 +5,10 @@
 package driver_inproc_cron
 
 import (
-	"context"
-	"sync"
-
 	"Wavelet/core"
 	"Wavelet/core/contracts"
+	"context"
+	"sync"
 )
 
 // Plugin implements core.Plugin and core.Driver for in-process cron job scheduling.

backend/plugins/drivers/driver_inproc_cron/plugin_test.go

@@ -4,6 +4,8 @@
 package driver_inproc_cron_test
 
 import (
+	"Wavelet/core"
+	"Wavelet/plugins/drivers/driver_inproc_cron"
 	"context"
 	"sync/atomic"
 	"testing"
@@ -11,9 +13,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
-	"Wavelet/core"
-	"Wavelet/plugins/drivers/driver_inproc_cron"
 )
 
 func TestInprocCronPlugin(t *testing.T) {

backend/plugins/drivers/driver_inproc_cron/scheduler.go

@@ -4,6 +4,10 @@
 package driver_inproc_cron
 
 import (
+	"Wavelet/core/contracts"
+	"Wavelet/core/extpoints"
+	"Wavelet/pkg/logger"
+	"Wavelet/pkg/util"
 	"context"
 	"encoding/json"
 	"errors"
@@ -12,11 +16,6 @@ import (
 	"time"
 
 	"github.com/robfig/cron/v3"
-
-	"Wavelet/core/contracts"
-	"Wavelet/core/extpoints"
-	"Wavelet/pkg/logger"
-	"Wavelet/pkg/util"
 )
 
 type inprocScheduler struct {