Bind app sessions to the platform auth session.

Clear local sessions when auth.ladill.com signs out and ping the platform session from keepalive.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Http/Controllers/Auth/SsoLoginController.php

@@ -138,6 +138,18 @@ class SsoLoginController extends Controller
         return redirect()->away($this->defaultSignedOutUrl());
     }
 
+    /** Platform session ended — clear this app and offer silent sign-in again. */
+    public function platformSignedOut(Request $request): RedirectResponse
+    {
+        Auth::logout();
+        $request->session()->invalidate();
+        $request->session()->regenerateToken();
+
+        return redirect()->route('sso.connect', [
+            'redirect' => (string) $request->query('redirect', ''),
+        ]);
+    }
+
     public function logoutBridge(Request $request): View
     {
         $return = $this->safeReturnUrl((string) $request->query('return', ''));