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/trade_service.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"time"
 
+	apperrors "with_you/internal/errors"
 	"with_you/internal/dto"
 	"with_you/internal/model"
 	"with_you/internal/pkg/cursor"
@@ -86,10 +87,10 @@ func (s *tradeService) GetByID(ctx context.Context, id string, currentUserID *st
 func (s *tradeService) Update(ctx context.Context, userID string, id string, req dto.UpdateTradeItemRequest) error {
 	item, err := s.tradeRepo.GetByID(ctx, id)
 	if err != nil {
-		return fmt.Errorf("trade item not found")
+		return apperrors.ErrNotFound
 	}
 	if item.UserID != userID {
-		return fmt.Errorf("not authorized")
+		return apperrors.ErrForbidden
 	}
 
 	if req.TradeType != nil {
@@ -124,10 +125,10 @@ func (s *tradeService) Update(ctx context.Context, userID string, id string, req
 func (s *tradeService) Delete(ctx context.Context, userID string, id string) error {
 	item, err := s.tradeRepo.GetByID(ctx, id)
 	if err != nil {
-		return fmt.Errorf("trade item not found")
+		return apperrors.ErrNotFound
 	}
 	if item.UserID != userID {
-		return fmt.Errorf("not authorized")
+		return apperrors.ErrForbidden
 	}
 	return s.tradeRepo.Delete(ctx, id)
 }
@@ -135,10 +136,10 @@ func (s *tradeService) Delete(ctx context.Context, userID string, id string) err
 func (s *tradeService) UpdateStatus(ctx context.Context, userID string, id string, status model.TradeItemStatus) error {
 	item, err := s.tradeRepo.GetByID(ctx, id)
 	if err != nil {
-		return fmt.Errorf("trade item not found")
+		return apperrors.ErrNotFound
 	}
 	if item.UserID != userID {
-		return fmt.Errorf("not authorized")
+		return apperrors.ErrForbidden
 	}
 	return s.tradeRepo.UpdateStatus(ctx, id, status)
 }