fix(ai): actually throw probe error out of probeDevServerReadiness so AI captures the failure synchronously

vibn-frontend/lib/dev-container.ts

@@ -767,6 +767,7 @@ export async function probeDevServerReadiness(
         `UPDATE fs_dev_servers SET state = 'failed' WHERE id = $1 AND project_id = $2 AND state != 'stopped'`,
         [serverId, projectId],
       );
+      throw new Error(`Probe failed with exit code ${r.exitCode}: ${r.stdout}`);
     }
   } catch (err) {
     console.error(
@@ -782,6 +783,7 @@ export async function probeDevServerReadiness(
       `UPDATE fs_dev_servers SET state = 'failed' WHERE id = $1 AND project_id = $2 AND state != 'stopped'`,
       [serverId, projectId],
     );
+    throw err;
   }
 }