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

internal/service/user_service.go

@@ -3,6 +3,7 @@ package service
 import (
 	"context"
 	"fmt"
+	"strconv"
 	"strings"
 	"time"
 
@@ -591,19 +592,20 @@ func (s *userServiceImpl) IsBlockedBatch(ctx context.Context, blockerID string,
 
 // GetFollowingList 获取关注列表（字符串参数版本）
 func (s *userServiceImpl) GetFollowingList(ctx context.Context, userID, page, pageSize string) ([]*model.User, error) {
-	// 转换字符串参数为整数
 	pageInt := 1
 	pageSizeInt := 20
 	if page != "" {
-		_, err := fmt.Sscanf(page, "%d", &pageInt)
-		if err != nil {
+		if v, err := strconv.Atoi(page); err != nil || v < 1 {
 			pageInt = 1
+		} else {
+			pageInt = v
 		}
 	}
 	if pageSize != "" {
-		_, err := fmt.Sscanf(pageSize, "%d", &pageSizeInt)
-		if err != nil {
+		if v, err := strconv.Atoi(pageSize); err != nil || v < 1 {
 			pageSizeInt = 20
+		} else {
+			pageSizeInt = v
 		}
 	}
 
@@ -613,19 +615,20 @@ func (s *userServiceImpl) GetFollowingList(ctx context.Context, userID, page, pa
 
 // GetFollowersList 获取粉丝列表（字符串参数版本）
 func (s *userServiceImpl) GetFollowersList(ctx context.Context, userID, page, pageSize string) ([]*model.User, error) {
-	// 转换字符串参数为整数
 	pageInt := 1
 	pageSizeInt := 20
 	if page != "" {
-		_, err := fmt.Sscanf(page, "%d", &pageInt)
-		if err != nil {
+		if v, err := strconv.Atoi(page); err != nil || v < 1 {
 			pageInt = 1
+		} else {
+			pageInt = v
 		}
 	}
 	if pageSize != "" {
-		_, err := fmt.Sscanf(pageSize, "%d", &pageSizeInt)
-		if err != nil {
+		if v, err := strconv.Atoi(pageSize); err != nil || v < 1 {
 			pageSizeInt = 20
+		} else {
+			pageSizeInt = v
 		}
 	}