fix(pi-bridge): shut down web server on session end

The web UI ChatController creates its own MeshStore with TCP servers
and sockets that were never cleaned up, leaking libuv handles that
kept the event loop alive and caused pi -p to hang indefinitely.

Store the WebServerHandle from tryStartWebServer() and close the
WebSocket server, HTTP server, and ChatController on session_shutdown.
The underlying MeshStore.shutdown() now unrefs all handles at init
time and before destroying them, so the event loop can exit cleanly.

Author: Mearman

src/bridges/pi/index.ts

@@ -18,14 +18,15 @@ import {
   ensureRegistered,
   formatDeliveryEvent,
 } from "../../core/index.js";
-import { tryStartWebServer } from "../user/web/server.js";
+import { tryStartWebServer, type WebServerHandle } from "../user/web/server.js";
 import { nanoid } from "../../core/nanoid.js";
 
 export default function (pi: ExtensionAPI) {
   const store = new MeshStore();
   const tool = new CommsTool(store);
 
   let agentId: string | undefined;
+  let webHandle: WebServerHandle | undefined;
 
   // Incoming messages arrive via TCP mesh — push immediately
   store.onDelivery = (_targetId: string, event) => {
@@ -40,8 +41,8 @@ export default function (pi: ExtensionAPI) {
   pi.on("session_start", async (_event, ctx) => {
     await store.init();
 
-    // Auto-start web UI (first bridge to bind port 3000 wins)
-    await tryStartWebServer();
+    // Auto-start web UI on a dynamic port
+    webHandle = tryStartWebServer();
 
     const reg = await ensureRegistered({
       store,
@@ -61,6 +62,12 @@ export default function (pi: ExtensionAPI) {
       await store.setAgentOffline(agentId);
     }
     await store.shutdown();
+    if (webHandle) {
+      webHandle.wss.close();
+      webHandle.server.close();
+      await webHandle.controller.shutdown();
+      webHandle = undefined;
+    }
   });
 
   // -----------------------------------------------------------------------