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/security.go

@@ -5,13 +5,13 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v5"
 )
 
 // SecurityHeadersMiddleware adds security headers to all responses
 func SecurityHeadersMiddleware() echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			// Add security headers
 			c.Response().Header().Set("X-Content-Type-Options", "nosniff")
 			c.Response().Header().Set("X-Frame-Options", "DENY")
@@ -30,7 +30,7 @@ func SecurityHeadersMiddleware() echo.MiddlewareFunc {
 // NOTE: Disabled for Docker self-hosted deployments - SSL is handled by reverse proxy
 func HTTPSRedirectMiddleware(httpsPort string) echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			// SSL is handled by proxy - no redirect needed
 			return next(c)
 		}
@@ -38,7 +38,7 @@ func HTTPSRedirectMiddleware(httpsPort string) echo.MiddlewareFunc {
 }
 
 // isTestMode checks if the application is running in test mode
-func isTestMode(c echo.Context) bool {
+func isTestMode(c *echo.Context) bool {
 	// Check for test mode header or environment
 	return c.Request().Header.Get("X-Test-Mode") == "true" ||
 		c.Request().Header.Get("X-Forwarded-Proto") == "http"
@@ -49,7 +49,7 @@ func isTestMode(c echo.Context) bool {
 // This middleware reads X-Forwarded-Proto and X-Forwarded-Host headers set by the proxy
 func SSLProxyMiddleware() echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			// Check for proxy headers
 			if proto := c.Request().Header.Get("X-Forwarded-Proto"); proto == "https" {
 				c.Request().URL.Scheme = "https"
@@ -113,7 +113,7 @@ func NewSecureCORSConfig() CORSSecurityConfig {
 // SecureCORSMiddleware creates CORS middleware with security
 func SecureCORSMiddleware(config CORSSecurityConfig) echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			origin := c.Request().Header.Get("Origin")
 
 			// Check if origin is allowed