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/device_auth_test.go

@@ -9,7 +9,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5/pgtype"
-	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v5"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -54,7 +54,7 @@ func TestDeviceAuth_Authenticate_BearerToken(t *testing.T) {
 	c := e.NewContext(req, rec)
 
 	// Create a handler that sets the device in context
-	next := func(c echo.Context) error {
+	next := func(c *echo.Context) error {
 		device, ok := c.Get("device").(database.Devices)
 		if ok {
 			c.Set("device_id", device.ID.Bytes)
@@ -206,7 +206,7 @@ func TestDeviceAuth_UpdateLastSeen(t *testing.T) {
 	deviceID := uuid.New()
 	c.Set("device_id", [16]byte(deviceID))
 
-	next := func(c echo.Context) error {
+	next := func(c *echo.Context) error {
 		// Simulate successful handler execution
 		return c.JSON(http.StatusOK, map[string]string{"status": "ok"})
 	}