feat: pet chat window replaces the Sagi panel; Windows pane attach no longer crashes the server

- Sagi: clicking the pet opens its chat window directly (PetChat + SagiInfo
  status strip, Needs you, Mute / Clear alerts); SagiPanel removed.
- Chat view answers Claude's unnumbered folder-trust prompt (parseBareMenu).
- pty-attach: resize/write after a Windows attach exited, and node-pty's pipe
  errors, no longer throw out of the WebSocket handler.
- restart-helper: the server started by an update logs to
  data/agenthub-server.log instead of discarding its output.

server/__tests__/self-restart.test.js

@@ -3,12 +3,17 @@
  * @description After an update, a server our service unit runs is restarted
  * by the unit, never by a detached replacement: v2.7.2 on the S3 system unit
  * left the replacement holding the port while `Restart=always` started the
- * unit every 3 s, each start exiting "already running".
+ * unit every 3 s, each start exiting "already running". Without a unit, the
+ * detached helper's replacement server logs to `data/agenthub-server.log`.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
 const { describe, it } = require("node:test");
 const assert = require("node:assert/strict");
+const fs = require("node:fs");
+const os = require("node:os");
+const path = require("node:path");
+const { execFileSync } = require("node:child_process");
 const { scheduleRestart, owningUnit } = require("../lib/self-restart");
 
 function deps(unit, restartAnswer = "restarted") {
@@ -23,8 +28,9 @@ function deps(unit, restartAnswer = "restarted") {
       },
     }),
     kill: () => calls.kill++,
-    spawnHelper: () => {
+    spawnHelper: (_exe, args) => {
       calls.spawn++;
+      calls.helperArgs = args;
       return { unref() {} };
     },
   };
@@ -84,5 +90,27 @@ describe("self-restart", () => {
     assert.equal(scheduleRestart("/r", d), "helper");
     assert.equal(d.calls.spawn, 1);
     assert.equal(d.calls.kill, 1);
+    // The new server logs where `agenthub start` does — never into nothing.
+    assert.equal(d.calls.helperArgs.at(-1), path.join("/r", "data", "agenthub-server.log"));
+  });
+
+  it("restart-helper appends the new server's stdout and stderr to the log", async () => {
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "restart-helper-"));
+    const entry = path.join(dir, "entry.js");
+    const log = path.join(dir, "data", "agenthub-server.log");
+    fs.writeFileSync(entry, 'console.log("up"); throw new Error("boom");\n');
+    const helper = path.join(__dirname, "..", "..", "scripts", "restart-helper.js");
+    // pid 0x7fffffff is never alive, so the helper restarts at once.
+    execFileSync(process.execPath, [helper, "2147483647", entry, log]);
+    const deadline = Date.now() + 5000;
+    let text = "";
+    while (Date.now() < deadline && !/boom/.test(text)) {
+      await new Promise((r) => setTimeout(r, 50));
+      text = fs.existsSync(log) ? fs.readFileSync(log, "utf8") : "";
+    }
+    fs.rmSync(dir, { recursive: true, force: true });
+    assert.match(text, /restart-helper: old server 2147483647 gone/);
+    assert.match(text, /^up$/m);
+    assert.match(text, /Error: boom/);
   });
 });