feat(connect-local): add Pi extension for local agent bridge

Monorepo Pi package with outbound WebSocket, pairing/reconnect flow,
presence reporting, and single-flight task.dispatch handling.

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

src/credentialStore.ts

@@ -0,0 +1,42 @@
+import { mkdir, readFile, rm, writeFile } from 'node:fs/promises';
+import path from 'node:path';
+
+export interface StoredReconnectCredential {
+  readonly projectName: string;
+  readonly credential: string;
+  readonly wsUrl: string;
+  readonly updatedAt: string;
+}
+
+export function credentialFilePath(baseDir: string): string {
+  return path.join(baseDir, 'local-agent-reconnect.json');
+}
+
+export async function loadReconnectCredential(baseDir: string): Promise<StoredReconnectCredential | undefined> {
+  try {
+    const raw = await readFile(credentialFilePath(baseDir), 'utf8');
+    const parsed = JSON.parse(raw) as StoredReconnectCredential;
+    if (!parsed?.projectName || !parsed?.credential || !parsed?.wsUrl) {
+      return undefined;
+    }
+    return parsed;
+  } catch {
+    return undefined;
+  }
+}
+
+export async function saveReconnectCredential(
+  baseDir: string,
+  value: StoredReconnectCredential,
+): Promise<void> {
+  await mkdir(baseDir, { recursive: true });
+  await writeFile(credentialFilePath(baseDir), JSON.stringify(value, null, 2), 'utf8');
+}
+
+export async function clearReconnectCredential(baseDir: string): Promise<void> {
+  try {
+    await rm(credentialFilePath(baseDir));
+  } catch {
+    /* already absent */
+  }
+}