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/repository/post_repo.go

@@ -7,6 +7,7 @@ import (
 
 	"with_you/internal/model"
 	"with_you/internal/pkg/cursor"
+	"with_you/internal/pkg/utils"
 
 	"gorm.io/gorm"
 )
@@ -510,10 +511,10 @@ func (r *postRepository) Search(keyword string, page, pageSize int) ([]*model.Po
 	// 搜索标题和内容
 	if keyword != "" {
 		if r.db.Dialector.Name() == "postgres" {
-			searchPattern := "%" + keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(keyword) + "%"
 			query = query.Where("title ILIKE ? OR content ILIKE ?", searchPattern, searchPattern)
 		} else {
-			searchPattern := "%" + keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(keyword) + "%"
 			query = query.Where("title LIKE ? OR content LIKE ?", searchPattern, searchPattern)
 		}
 	}
@@ -877,10 +878,10 @@ func (r *postRepository) AdminList(query AdminPostListQuery) ([]*model.Post, int
 	// 关键词搜索（标题或内容）
 	if query.Keyword != "" {
 		if r.db.Dialector.Name() == "postgres" {
-			searchPattern := "%" + query.Keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(query.Keyword) + "%"
 			db = db.Where("title ILIKE ? OR content ILIKE ?", searchPattern, searchPattern)
 		} else {
-			searchPattern := "%" + query.Keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(query.Keyword) + "%"
 			db = db.Where("title LIKE ? OR content LIKE ?", searchPattern, searchPattern)
 		}
 	}
@@ -1125,10 +1126,10 @@ func (r *postRepository) SearchPostsByCursor(ctx context.Context, keyword string
 	// 搜索标题和内容
 	if keyword != "" {
 		if r.db.Dialector.Name() == "postgres" {
-			searchPattern := "%" + keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(keyword) + "%"
 			query = query.Where("title ILIKE ? OR content ILIKE ?", searchPattern, searchPattern)
 		} else {
-			searchPattern := "%" + keyword + "%"
+			searchPattern := "%" + utils.EscapeLikeWildcard(keyword) + "%"
 			query = query.Where("title LIKE ? OR content LIKE ?", searchPattern, searchPattern)
 		}
 	}