refactor(router): update routes and middleware for Echo v5

Update all router files to use Echo v5 APIs and type signatures.

Changes in router.go:
- Replace echomiddleware.Logger() with RequestLogger() (line 144)
- Update import from echo/v4 to echo/v5

Changes in frontend.go:
- Update frontend handler signatures to use *echo.Context
- Fix middleware registration for v5 compatibility

Changes in auth.go, library.go, scanner.go, sync.go, helpers.go:
- Update handler function signatures to *echo.Context
- Ensure consistent type usage across all route handlers

All routes now properly implement Echo v5's middleware and handler patterns.

internal/router/router.go

@@ -21,9 +21,9 @@ import (
 	"github.com/golang-jwt/jwt/v5"
 	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5/pgtype"
-	echojwt "github.com/labstack/echo-jwt/v4"
-	"github.com/labstack/echo/v4"
-	echomiddleware "github.com/labstack/echo/v4/middleware"
+	echojwt "github.com/labstack/echo-jwt/v5"
+	"github.com/labstack/echo/v5"
+	echomiddleware "github.com/labstack/echo/v5/middleware"
 )
 
 // CustomValidator wraps the go-playground validator
@@ -71,7 +71,7 @@ func createJWTMiddleware(cfg *Config) echo.MiddlewareFunc {
 		SigningKey:  []byte(cfg.Cfg.JWTSecret),
 		ContextKey:  "user",
 		TokenLookup: "cookie:token,header:Authorization:Bearer ",
-		SuccessHandler: func(c echo.Context) {
+		SuccessHandler: func(c *echo.Context) error {
 			token := c.Get("user").(*jwt.Token)
 			claims := token.Claims.(jwt.MapClaims)
 			c.Set("user_id", claims["user_id"])
@@ -83,8 +83,7 @@ func createJWTMiddleware(cfg *Config) echo.MiddlewareFunc {
 			userIDStr, _ := claims["user_id"].(string)
 			userUUID, err := uuid.Parse(userIDStr)
 			if err != nil {
-				c.Error(echo.NewHTTPError(http.StatusBadRequest, "invalid user ID in token"))
-				return
+				return echo.NewHTTPError(http.StatusBadRequest, "invalid user ID in token")
 			}
 
 			c.Set("user", database.Users{
@@ -93,8 +92,9 @@ func createJWTMiddleware(cfg *Config) echo.MiddlewareFunc {
 				Username: claims["user_username"].(string),
 				Role:     claims["user_role"].(string),
 			})
+			return nil
 		},
-		ErrorHandler: func(c echo.Context, err error) error {
+		ErrorHandler: func(c *echo.Context, err error) error {
 			// Check if this is a page request (browser navigation)
 			if wantsHTML(c.Request().Header) {
 				// Page request → Redirect to login with message
@@ -114,7 +114,7 @@ func createJWTMiddleware(cfg *Config) echo.MiddlewareFunc {
 // ensureUserExistsMiddleware checks if the authenticated user still exists in the database
 func ensureUserExistsMiddleware(cfg *Config) echo.MiddlewareFunc {
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
+		return func(c *echo.Context) error {
 			userIDStr, ok := c.Get("user_id").(string)
 			if !ok {
 				return next(c)
@@ -184,7 +184,7 @@ func RegisterRoutes(cfg *Config) *handlers.Handler {
 	e.Validator = &CustomValidator{validator: v}
 
 	// Global middleware
-	e.Use(echomiddleware.Logger())
+	e.Use(echomiddleware.RequestLogger())
 	e.Use(echomiddleware.Recover())
 	e.Use(echomiddleware.CORS())
 	e.Use(ratelimit.RequestTracingMiddleware(cfg.Cfg))
@@ -227,7 +227,7 @@ func RegisterRoutes(cfg *Config) *handlers.Handler {
 	e.Static("/static", "web/static")
 
 	// Catch-all 404 handler - must be last
-	e.GET("/*", func(c echo.Context) error {
+	e.GET("/*", func(c *echo.Context) error {
 		var buf bytes.Buffer
 		err := templates.ErrorPage("Page not found", "404").Render(c.Request().Context(), &buf)
 		if err != nil {