fix(db): cast project_id to uuid in agent_sessions INSERT query

app/api/projects/[projectId]/agent/sessions/route.ts

@@ -83,7 +83,7 @@ export async function POST(
     // Create the session row
     const rows = await query<{ id: string }>(
       `INSERT INTO agent_sessions (project_id, app_name, app_path, task, status, started_at)
-       VALUES ($1::text, $2, $3, $4, 'running', now())
+       VALUES ($1::uuid, $2, $3, $4, 'running', now())
        RETURNING id`,
       [projectId, appName, appPath, task.trim()]
     );