feat: main.go 接入配置 + graceful shutdown + logger 迁移

- main.go: 接入 config.Load() 替换硬编码 :8080
- main.go: 添加 signal.NotifyContext + http.Server.Shutdown（10s drain）
- main.go: 初始化 Zap 日志，prod 环境切换 Gin release 模式
- ws/handler.go: 所有 log.Printf 替换为 logger.Log 结构化日志
- 修复 .gitignore 排除规则（/server 仅匹配根目录二进制）
- 新增 zap、viper 依赖

backend/cmd/server/main.go

@@ -1,18 +1,45 @@
 package main
 
 import (
-	"log"
+	"context"
+	"errors"
+	"net/http"
+	"os/signal"
+	"syscall"
 	"time"
 
 	"github.com/gin-gonic/gin"
 
+	"github.com/hhs/camtalk/internal/config"
+	"github.com/hhs/camtalk/internal/logger"
 	"github.com/hhs/camtalk/internal/ws"
 )
 
 var startTime = time.Now()
 
 func main() {
-	r := gin.Default()
+	// 加载配置
+	cfg, err := config.Load()
+	if err != nil {
+		panic("failed to load config: " + err.Error())
+	}
+
+	// 初始化日志
+	logger.Init(cfg.Log.Level, cfg.Log.Format)
+	defer logger.Sync()
+
+	logger.Log.Infow("config loaded",
+		"env", cfg.App.Env,
+		"addr", cfg.Server.Addr(),
+	)
+
+	// Gin 模式
+	if cfg.App.Env == "prod" {
+		gin.SetMode(gin.ReleaseMode)
+	}
+
+	r := gin.New()
+	r.Use(gin.Recovery())
 
 	// REST API
 	api := r.Group("/api")
@@ -23,18 +50,43 @@ func main() {
 	// WebSocket
 	r.GET("/ws", ws.ServeWS)
 
-	log.Println("CamTalk gateway starting on :8080")
-	if err := r.Run(":8080"); err != nil {
-		log.Fatalf("failed to start server: %v", err)
+	// HTTP Server
+	srv := &http.Server{
+		Addr:         cfg.Server.Addr(),
+		Handler:      r,
+		ReadTimeout:  time.Duration(cfg.Server.ReadTimeout) * time.Second,
+		WriteTimeout: time.Duration(cfg.Server.WriteTimeout) * time.Second,
 	}
+
+	// Graceful shutdown
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	go func() {
+		logger.Log.Infow("server starting", "addr", srv.Addr)
+		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			logger.Log.Fatalw("listen failed", "error", err)
+		}
+	}()
+
+	<-ctx.Done()
+	logger.Log.Info("shutting down...")
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		logger.Log.Errorw("shutdown error", "error", err)
+	}
+	logger.Log.Info("server stopped")
 }
 
 // healthHandler 健康检查。
 func healthHandler(c *gin.Context) {
 	c.JSON(200, gin.H{
-		"status":         "ok",
-		"version":        "0.1.0",
-		"uptime":         time.Since(startTime).String(),
+		"status":          "ok",
+		"version":         "0.1.0",
+		"uptime":          time.Since(startTime).String(),
 		"active_sessions": 0, // TODO: 接入 Session Manager
 	})
 }