test(827): capture Gate0 runtime evidence

docs/compaction-refresh/probes/p1_pi_extension.ts

@@ -0,0 +1,35 @@
+import type { ExtensionAPI } from '@earendil-works/pi-coding-agent';
+import net from 'node:net';
+
+async function brokerRequest(payload: Record<string, unknown>): Promise<Record<string, unknown>> {
+  const socketPath = process.env['GATE0_BROKER_SOCKET'];
+  if (!socketPath) throw new Error('GATE0_BROKER_SOCKET missing');
+  return await new Promise((resolve, reject) => {
+    const socket = net.createConnection(socketPath);
+    let buffer = '';
+    socket.setEncoding('utf8');
+    socket.on('connect', () => socket.write(`${JSON.stringify(payload)}\n`));
+    socket.on('data', (chunk) => {
+      buffer += chunk;
+      const newline = buffer.indexOf('\n');
+      if (newline < 0) return;
+      socket.end();
+      resolve(JSON.parse(buffer.slice(0, newline)) as Record<string, unknown>);
+    });
+    socket.on('error', reject);
+  });
+}
+
+export default function register(pi: ExtensionAPI) {
+  pi.on('session_start', async () => {
+    const response = await brokerRequest({ action: 'resolve-hook', runtime: 'pi-extension' });
+    if (response['decision'] !== 'ACCEPT') {
+      throw new Error(`P1 broker rejected Pi extension ancestry: ${response['reason']}`);
+    }
+  });
+
+  pi.registerCommand('gate0-p1-ready', {
+    description: 'Return only after the P1 session_start ancestry hook completed',
+    handler: async () => undefined,
+  });
+}