feat: enhance security with IP banning, ownership checks, and SSRF protection

Add comprehensive security improvements across the application:

- **IP-based login protection**: Implement IP ban system tracking login failures, auto-banning after threshold exceeded
- **Ownership verification**: Add userID parameter to Delete/Update operations for posts and comments to prevent unauthorized modifications
- **SSRF protection**: Add URL and resolved host validation for image URLs in chat and OpenAI client
- **SQL injection prevention**: Add EscapeLikeWildcard utility to escape special characters in LIKE queries
- **HTTP security**: Configure server timeouts and add security headers middleware
- **Rate limiting**: Refactor to support configurable duration and per-endpoint rate limits for auth routes
- **Error handling**: Standardize error responses using HandleError and proper error types

cmd/server/app.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"time"
 
 	"with_you/internal/config"
 	"with_you/internal/grpc/runner"
@@ -72,8 +73,12 @@ func (a *App) Start(ctx context.Context) error {
 	)
 
 	a.Server = &http.Server{
-		Addr:    addr,
-		Handler: a.Router.Engine(),
+		Addr:              addr,
+		Handler:           a.Router.Engine(),
+		ReadHeaderTimeout: 10 * time.Second,
+		ReadTimeout:       30 * time.Second,
+		WriteTimeout:      60 * time.Second,
+		IdleTimeout:       120 * time.Second,
 	}
 
 	// 4. 启动 HTTP 服务器