feat: add Pi subagent scheduler and child runtime

tests/unit/pi-managed-worker-opener.test.ts

@@ -161,7 +161,7 @@ describe('managed Pi worker opener', () => {
       expect(argv).toContain('grilling');
       expect(argv).toContain('--session-id');
       expect(argv).toContain('--extension');
-      expect(argv).toContain('makelore-runtime-v1.mjs');
+      expect(argv).toContain('makelore-runtime-v2.mjs');
       expect(options.additionalArgs?.filter((argument) => argument === '--extension')).toHaveLength(1);
       expect(argv).not.toContain('PRIVATE MANAGED PROMPT');
       expect(argv).not.toContain('provider-secret-value');