refactor: improve system stability, performance, and code structure

This commit introduces several architectural improvements and optimizations across the codebase:

- **Performance & Reliability**:
  - Implemented Redis pipelining in `ConversationCache.CacheMessage` to reduce network round-trips.
  - Added a circuit breaker to the JPush client to prevent cascading failures.
  - Introduced batch deletion and batch member addition capabilities in repositories.
  - Added message idempotency support using `client_msg_id` and a Redis-based cache.
  - Optimized WebSocket handling with connection limits (total and per-user) and improved error logging.

- **Code Refactoring**:
  - Refactored `Router` to use a `RouterDeps` struct, simplifying the constructor and improving maintainability.
  - Unified model ID generation logic using new `id_helper.go` (supporting UUID and Snowflake).
  - Standardized JSON serialization/deserialization in models using `json_helper.go`.
  - Refactored DTO conversion logic, specifically for `UserResponse` (using functional options) and `Report` responses.
  - Removed redundant/deprecated DTOs like `PostDetailResponse` and `TradeItemDetailResponse`.

- **Cache Improvements**:
  - Enhanced `LayeredCache` with `SetRaw` to avoid double-encoding when promoting values from Redis to local cache.
  - Added `DeleteBatch` support to the cache interface.

- **Other Changes**:
  - Cleaned up `config.go` by removing redundant default values and explicit environment variable overrides.
  - Improved WebSocket registration flow to handle connection limits gracefully.

cmd/server/app.go

@@ -8,6 +8,7 @@ import (
 
 	"with_you/internal/config"
 	"with_you/internal/grpc/runner"
+	"with_you/internal/pkg/ws"
 	"with_you/internal/router"
 	"with_you/internal/service"
 
@@ -24,6 +25,7 @@ type App struct {
 	HotRankWorker *service.HotRankWorker
 	GRPCServer    *runner.Server
 	Server        *http.Server
+	WsHub         *ws.Hub
 	Logger        *zap.Logger
 }
 
@@ -35,6 +37,7 @@ func NewApp(
 	pushService service.PushService,
 	hotRankWorker *service.HotRankWorker,
 	grpcServer *runner.Server,
+	wsHub *ws.Hub,
 	logger *zap.Logger,
 ) *App {
 	return &App{
@@ -44,6 +47,7 @@ func NewApp(
 		PushService:   pushService,
 		HotRankWorker: hotRankWorker,
 		GRPCServer:    grpcServer,
+		WsHub:         wsHub,
 		Logger:        logger,
 	}
 }
@@ -97,7 +101,13 @@ func (a *App) Start(ctx context.Context) error {
 func (a *App) Stop(ctx context.Context) error {
 	a.Logger.Info("Shutting down server")
 
-	// 1. 停止 HTTP 服务器
+	// 1. 关闭所有 WebSocket 连接
+	if a.WsHub != nil {
+		a.Logger.Info("Closing WebSocket connections")
+		a.WsHub.CloseAllConnections()
+	}
+
+	// 3. 停止 HTTP 服务器
 	if a.Server != nil {
 		a.Logger.Info("Stopping HTTP server")
 		if err := a.Server.Shutdown(ctx); err != nil {
@@ -107,13 +117,13 @@ func (a *App) Stop(ctx context.Context) error {
 		}
 	}
 
-	// 2. 停止 gRPC 服务器
+	// 4. 停止 gRPC 服务器
 	if a.GRPCServer != nil {
 		a.Logger.Info("Stopping gRPC server")
 		a.GRPCServer.Stop()
 	}
 
-	// 3. 停止推送 Worker
+	// 5. 停止推送 Worker
 	a.Logger.Info("Stopping push worker")
 	a.PushService.StopPushWorker()
 
@@ -122,7 +132,7 @@ func (a *App) Stop(ctx context.Context) error {
 		a.HotRankWorker.Stop()
 	}
 
-	// 4. 关闭数据库连接
+	// 6. 关闭数据库连接
 	a.Logger.Info("Closing database connection")
 	sqlDB, err := a.DB.DB()
 	if err == nil {