diff --git a/backend/cmd/desktop/main.go b/backend/cmd/desktop/main.go
index 6721bb8..bfceb2b 100644
--- a/backend/cmd/desktop/main.go
+++ b/backend/cmd/desktop/main.go
@@ -12,11 +12,11 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
-	"syscall"
 	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/getlantern/systray"
+	"github.com/gofrs/flock"
 	"github.com/pressly/goose/v3"
 	"go.uber.org/zap"
 	"gorm.io/driver/sqlite"
@@ -47,11 +47,12 @@ var (
 func main() {
 	port := 9826
 
-	if err := acquireSingleInstance(); err != nil {
+	singleLock := NewSingletonLock(filepath.Join(os.TempDir(), "nex-gateway.lock"))
+	if err := singleLock.Lock(); err != nil {
 		showError("Nex Gateway", "已有 Nex 实例运行")
 		os.Exit(1)
 	}
-	defer releaseSingleInstance()
+	defer singleLock.Unlock()
 
 	if err := checkPortAvailable(port); err != nil {
 		showError("Nex Gateway", err.Error())
@@ -89,10 +90,21 @@ func main() {
 	modelRepo := repository.NewModelRepository(db)
 	statsRepo := repository.NewStatsRepository(db)
 
-	providerService := service.NewProviderService(providerRepo, modelRepo)
-	modelService := service.NewModelService(modelRepo, providerRepo)
-	routingService := service.NewRoutingService(modelRepo, providerRepo)
-	statsService := service.NewStatsService(statsRepo)
+	routingCache := service.NewRoutingCache(modelRepo, providerRepo, zapLogger)
+	if err := routingCache.Preload(); err != nil {
+		zapLogger.Warn("缓存预热失败，将使用懒加载", zap.Error(err))
+	}
+
+	statsBuffer := service.NewStatsBuffer(statsRepo, zapLogger,
+		service.WithFlushInterval(5*time.Second),
+		service.WithFlushThreshold(100))
+	statsBuffer.Start()
+	defer statsBuffer.Stop()
+
+	providerService := service.NewProviderService(providerRepo, modelRepo, routingCache)
+	modelService := service.NewModelService(modelRepo, providerRepo, routingCache)
+	routingService := service.NewRoutingService(routingCache)
+	statsService := service.NewStatsService(statsRepo, statsBuffer)
 
 	registry := conversion.NewMemoryRegistry()
 	if err := registry.Register(openai.NewAdapter()); err != nil {
@@ -378,31 +390,29 @@ func checkPortAvailable(port int) error {
 	return nil
 }
 
-var lockFile *os.File
+type SingletonLock struct {
+	flock *flock.Flock
+}
 
-func acquireSingleInstance() error {
-	lockPath := filepath.Join(os.TempDir(), "nex-gateway.lock")
+func NewSingletonLock(lockPath string) *SingletonLock {
+	return &SingletonLock{
+		flock: flock.New(lockPath),
+	}
+}
 
-	f, err := os.OpenFile(lockPath, os.O_CREATE|os.O_RDWR, 0666)
+func (s *SingletonLock) Lock() error {
+	locked, err := s.flock.TryLock()
 	if err != nil {
 		return err
 	}
-
-	err = syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
-	if err != nil {
-		f.Close()
+	if !locked {
 		return fmt.Errorf("已有实例运行")
 	}
-
-	lockFile = f
 	return nil
 }
 
-func releaseSingleInstance() {
-	if lockFile != nil {
-		syscall.Flock(int(lockFile.Fd()), syscall.LOCK_UN)
-		lockFile.Close()
-	}
+func (s *SingletonLock) Unlock() {
+	s.flock.Unlock()
 }
 
 func openBrowser(url string) error {
diff --git a/backend/cmd/desktop/singleton_test.go b/backend/cmd/desktop/singleton_test.go
index 03031cf..c26b13f 100644
--- a/backend/cmd/desktop/singleton_test.go
+++ b/backend/cmd/desktop/singleton_test.go
@@ -3,37 +3,56 @@ package main
 import (
 	"os"
 	"path/filepath"
-	"syscall"
 	"testing"
 )
 
-func TestAcquireSingleInstance(t *testing.T) {
-	lockPath := filepath.Join(os.TempDir(), "nex-gateway-test.lock")
-	
-	origLockFile := lockFile
-	lockFile = nil
-	defer func() { lockFile = origLockFile }()
-
-	f, err := os.OpenFile(lockPath, os.O_CREATE|os.O_RDWR, 0666)
-	if err != nil {
-		t.Fatalf("无法创建锁文件: %v", err)
-	}
-	defer f.Close()
+func TestSingletonLock_FirstLockSuccess(t *testing.T) {
+	lockPath := filepath.Join(os.TempDir(), "nex-gateway-test-first.lock")
 	defer os.Remove(lockPath)
 
-	err = syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
-	if err != nil {
-		t.Fatalf("无法获取文件锁: %v", err)
+	lock := NewSingletonLock(lockPath)
+	if err := lock.Lock(); err != nil {
+		t.Fatalf("首次加锁应成功，但返回错误: %v", err)
 	}
-	defer syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
-
-	t.Log("单实例锁测试通过")
+	defer lock.Unlock()
 }
 
-func TestReleaseSingleInstance(t *testing.T) {
-	lockFile = nil
-	
-	releaseSingleInstance()
-	
-	t.Log("释放空锁测试通过")
+func TestSingletonLock_DuplicateLockFails(t *testing.T) {
+	lockPath := filepath.Join(os.TempDir(), "nex-gateway-test-dup.lock")
+	defer os.Remove(lockPath)
+
+	lock1 := NewSingletonLock(lockPath)
+	if err := lock1.Lock(); err != nil {
+		t.Fatalf("首次加锁应成功: %v", err)
+	}
+	defer lock1.Unlock()
+
+	lock2 := NewSingletonLock(lockPath)
+	err := lock2.Lock()
+	if err == nil {
+		lock2.Unlock()
+		t.Fatal("重复加锁应失败，但返回 nil")
+	}
+}
+
+func TestSingletonLock_UnlockThenRelock(t *testing.T) {
+	lockPath := filepath.Join(os.TempDir(), "nex-gateway-test-relock.lock")
+	defer os.Remove(lockPath)
+
+	lock1 := NewSingletonLock(lockPath)
+	if err := lock1.Lock(); err != nil {
+		t.Fatalf("首次加锁应成功: %v", err)
+	}
+	lock1.Unlock()
+
+	lock2 := NewSingletonLock(lockPath)
+	if err := lock2.Lock(); err != nil {
+		t.Fatalf("释放后重新加锁应成功: %v", err)
+	}
+	lock2.Unlock()
+}
+
+func TestSingletonLock_UnlockWithoutLock(t *testing.T) {
+	lock := NewSingletonLock(filepath.Join(os.TempDir(), "nex-gateway-test-nil.lock"))
+	lock.Unlock()
 }
diff --git a/backend/go.mod b/backend/go.mod
index 99e3d99..7ce3c5f 100644
--- a/backend/go.mod
+++ b/backend/go.mod
@@ -13,6 +13,7 @@ require (
 	github.com/getlantern/systray v1.2.2
 	github.com/gin-gonic/gin v1.12.0
 	github.com/go-playground/validator/v10 v10.30.2
+	github.com/gofrs/flock v0.13.0
 	github.com/google/uuid v1.6.0
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/pressly/goose/v3 v3.27.0
@@ -102,7 +103,6 @@ require (
 	github.com/gobwas/glob v0.2.3 // indirect
 	github.com/goccy/go-json v0.10.5 // indirect
 	github.com/goccy/go-yaml v1.19.2 // indirect
-	github.com/gofrs/flock v0.12.1 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/golangci/dupl v0.0.0-20250308024227-f665c8d69b32 // indirect
 	github.com/golangci/go-printf-func-name v0.1.0 // indirect
diff --git a/backend/go.sum b/backend/go.sum
index d6f1911..9c89ceb 100644
--- a/backend/go.sum
+++ b/backend/go.sum
@@ -239,8 +239,8 @@ github.com/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
 github.com/goccy/go-json v0.10.5/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/goccy/go-yaml v1.19.2 h1:PmFC1S6h8ljIz6gMRBopkjP1TVT7xuwrButHID66PoM=
 github.com/goccy/go-yaml v1.19.2/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
-github.com/gofrs/flock v0.12.1 h1:MTLVXXHf8ekldpJk3AKicLij9MdwOWkZ+a/jHHZby9E=
-github.com/gofrs/flock v0.12.1/go.mod h1:9zxTsyu5xtJ9DK+1tFZyibEV7y3uwDxPPfbxeeHCoD0=
+github.com/gofrs/flock v0.13.0 h1:95JolYOvGMqeH31+FC7D2+uULf6mG61mEZ/A8dRYMzw=
+github.com/gofrs/flock v0.13.0/go.mod h1:jxeyy9R1auM5S6JYDBhDt+E2TCo7DkratH4Pgi8P+Z0=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
diff --git a/openspec/specs/cross-platform-singleton/spec.md b/openspec/specs/cross-platform-singleton/spec.md
new file mode 100644
index 0000000..6561736
--- /dev/null
+++ b/openspec/specs/cross-platform-singleton/spec.md
@@ -0,0 +1,53 @@
+# 跨平台单实例锁
+
+## Purpose
+
+TBD - 提供跨平台单实例文件锁机制，使用 `github.com/gofrs/flock` 封装，支持 Windows、macOS、Linux 三平台。
+
+## Requirements
+
+### Requirement: 跨平台单实例文件锁
+
+系统 SHALL 提供跨平台的单实例文件锁机制，使用 `github.com/gofrs/flock` 实现，在 Windows、macOS、Linux 上均可正常工作。
+
+#### Scenario: 首次加锁成功
+- **WHEN** 调用 `NewSingletonLock(lockPath)` 创建锁实例并调用 `Lock()`
+- **AND** 锁文件未被其他进程持有
+- **THEN** 加锁成功，返回 `nil`
+
+#### Scenario: 重复加锁失败
+- **WHEN** 另一个进程已持有同一锁文件的排他锁
+- **AND** 调用 `Lock()`
+- **THEN** 加锁失败，返回错误
+
+#### Scenario: 释放锁
+- **WHEN** 调用 `Unlock()`
+- **THEN** 排他锁被释放
+- **AND** 其他进程可以成功加锁
+
+#### Scenario: 进程崩溃后锁自动释放
+- **WHEN** 持有锁的进程异常退出（崩溃、kill）
+- **THEN** 操作系统自动释放文件锁
+- **AND** 新进程可以成功加锁
+
+> 注：此场景由操作系统和 `gofrs/flock` 库保证，无需显式单元测试。
+
+### Requirement: 锁路径参数化
+
+`SingletonLock` SHALL 通过构造函数参数接收锁文件路径，支持不同运行上下文使用不同锁文件。
+
+#### Scenario: 正式运行锁路径
+- **WHEN** 桌面应用正常启动
+- **THEN** 使用 `%TEMP%/nex-gateway.lock` 作为锁文件路径
+
+#### Scenario: 测试运行锁路径
+- **WHEN** 运行 `go test`
+- **THEN** 测试代码使用独立的锁文件路径（如 `%TEMP%/nex-gateway-test.lock`）
+- **AND** 与正式版锁文件互不影响
+
+#### Scenario: 锁路径隔离
+- **WHEN** 正式版桌面应用正在运行
+- **AND** 同时执行 `go test`
+- **THEN** 正式版持有 `nex-gateway.lock`
+- **AND** 测试持有 `nex-gateway-test.lock`
+- **AND** 两者互不阻塞
diff --git a/openspec/specs/desktop-app/spec.md b/openspec/specs/desktop-app/spec.md
index 9758f23..f509a25 100644
--- a/openspec/specs/desktop-app/spec.md
+++ b/openspec/specs/desktop-app/spec.md
@@ -12,16 +12,23 @@ TBD - 提供跨平台桌面应用支持，将后端服务与前端静态资源
 
 #### Scenario: 双击启动
 - **WHEN** 用户双击桌面应用可执行文件
-- **THEN** 系统启动后端服务
+- **THEN** 系统使用 `gofrs/flock` 尝试获取排他文件锁
+- **AND** 锁文件路径为系统临时目录下的 `nex-gateway.lock`
+- **AND** 系统启动后端服务
 - **AND** 系统托盘图标出现
 - **AND** 浏览器自动打开 `http://localhost:9826` 显示管理界面
 
 #### Scenario: 单实例检查
 - **WHEN** 用户尝试启动第二个实例
-- **THEN** 系统检测到已有实例运行
+- **THEN** 系统检测到已有实例持有文件锁
 - **AND** 显示错误提示"已有 Nex 实例运行"
 - **AND** 新实例退出
 
+#### Scenario: 退出释放锁
+- **WHEN** 用户点击托盘菜单"退出"
+- **THEN** 系统释放文件锁
+- **AND** 应用进程退出
+
 ### Requirement: 系统托盘
 
 系统 SHALL 提供跨平台系统托盘功能，支持托盘图标和菜单。