test: update integration tests for Echo v5 compatibility

Update all integration test files to work with Echo v5 changes.

Changes in new_fixes_test.go:
- Update test helper signatures for *echo.Context
- Fix context handling in test assertions

Changes in security_test.go:
- Update security test signatures for Echo v5

Changes in test_helpers.go:
- Update test setup for Echo v5
- Fix context type usage in test helpers

Changes in websocket_test.go:
- Update WebSocket test for Echo v5 compatibility
- Fix response wrapper usage for v5 API
- Update hijacker interface expectations
  - Echo v5 now properly implements rwUnwrapper
  - WebSocket upgrade works natively without custom wrappers

All tests now properly work with Echo v5's pointer-based context
and improved WebSocket support.

cmd/server/tests/security_test.go

@@ -7,7 +7,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v5"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -94,7 +94,7 @@ func TestRateLimiterSecurity(t *testing.T) {
 	rl := ratelimit.NewRateLimiter(config)
 	rateLimitMiddleware := ratelimit.RateLimiterMiddleware(rl)
 
-	handler := func(c echo.Context) error {
+	handler := func(c *echo.Context) error {
 		return c.String(http.StatusOK, "ok")
 	}