feat(auth): show session expired message on login page

- Update Login template to accept sessionExpired boolean parameter
- Add conditional message box when session=expired query param present
- Update /login route handler to parse session query param
- Pass sessionExpired flag to Login template
- Regenerate login_templ.go with new signature

Displays friendly message: "Your session has expired. Please log in
again to continue." when users are redirected due to expired sessions.

internal/router/frontend.go

@@ -39,7 +39,8 @@ func registerFrontendRoutes(cfg *Config) {
 	// Public routes for login and registration pages
 	e.GET("/login", func(c echo.Context) error {
 		var buf bytes.Buffer
-		err := templates.Login().Render(c.Request().Context(), &buf)
+		sessionExpired := c.QueryParam("session") == "expired"
+		err := templates.Login(sessionExpired).Render(c.Request().Context(), &buf)
 		if err != nil {
 			return err
 		}