refactor(middleware): fix type signatures for Echo v5 compatibility

Update all middleware functions to use *echo.Context (pointer) instead of echo.Context (value) as required by Echo v5.

Changes in device_auth.go:
- Update DeviceAuthMiddleware() signature (line 38)
- Update validateDeviceAuth() signature (line 170)
- Update RequireDeviceAuth() signature (line 212)

Changes in error_handler.go:
- Update RespondWithError() signature (line 44)
- Update RespondWithHTTPError() signature (line 69)
- Update WrapHandler() to accept *echo.Context (line 82)
- Fix context passing in WrapHandler() (c is already pointer)

Changes in rate_limiter.go:
- Update RateLimiterMiddleware() signature (line 102)

Changes in request_tracing.go:
- Update RequestTracingMiddleware() signature (line 48)
- Fix Response() dereference for v5 API (line 264)
  - Use *c.Response() to get http.ResponseWriter

Changes in security.go:
- Update SecurityHeadersMiddleware() signature (line 14)

Changes in device_auth_test.go:
- Update test helper signatures

Changes in middleware_test.go:
- Remove unused import

All middleware now properly implements Echo v5's pointer-based context pattern.

internal/middleware/request_tracing.go

@@ -10,7 +10,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
-	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v5"
 )
 
 type responseWriter struct {
@@ -45,7 +45,7 @@ type RequestLogEntry struct {
 
 func RequestTracingMiddleware(cfg *config.Config) echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			start := time.Now()
 
 			requestID := c.Response().Header().Get(echo.HeaderXRequestID)
@@ -55,9 +55,9 @@ func RequestTracingMiddleware(cfg *config.Config) echo.MiddlewareFunc {
 			}
 
 			recorder := &responseWriter{
-				ResponseWriter: c.Response().Writer,
+				ResponseWriter: c.Response(),
 			}
-			c.Response().Writer = recorder
+			c.SetResponse(recorder)
 
 			var body interface{}
 			if c.Request().Body != nil && c.Request().Method != "GET" {
@@ -105,7 +105,7 @@ func RequestTracingMiddleware(cfg *config.Config) echo.MiddlewareFunc {
 				RemoteAddr:   c.RealIP(),
 				UserAgent:    c.Request().UserAgent(),
 				Duration:     duration,
-				StatusCode:   c.Response().Status,
+				StatusCode:   c.Response().(*echo.Response).Status,
 				ResponseSize: int64(recorder.size),
 			}