feat(cli): add /update slash command to CLI and TUI (#23854)

* feat: add /update slash command to CLI and TUI

* test(cli): add Python tests for /update slash command

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

* fix(cli): address Copilot review for /update slash command

Route classic CLI /update through prompt_toolkit modal confirmation and
defer relaunch to the main-thread cleanup path after app.exit(). Tighten
Y/n semantics, add Python wrapper and catalog coverage tests, and assert
/update stays visible in the TUI command catalog.

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

* fix(cli): address review feedback on /update command

- Replace raw input() with _prompt_text_input_modal in _handle_update_command
  to avoid EOF/hang/keystroke-leak races with prompt_toolkit's stdin ownership
- Fix confirmation logic: only proceed on recognized affirmative aliases
  (y/yes/1/ok); cancel on everything else including empty string, typos,
  and unrecognized input — matches all other [Y/n] prompts in the codebase
- Route relaunch through main-thread shutdown path: set _pending_relaunch
  and return False from process_command so process_loop triggers app.exit();
  run() then calls relaunch() after prompt_toolkit has restored terminal modes
  and after cleanup — safe on both POSIX (execvp) and Windows (subprocess+exit)
- Fix misleading docstring in test_update_command.py: the Vitest only covers
  the TypeScript slash handler that emits code 42, not the Python wrapper
  branch that acts on it
- Rewrite tests to use SimpleNamespace pattern (like test_destructive_slash_confirm)
  so _prompt_text_input_modal can be stubbed directly
- Add Python test for _launch_tui exit-code-42 → relaunch branch in main.py

Agent-Logs-Url: https://github.com/NousResearch/hermes-agent/sessions/f6da68cf-e7b1-4b7a-aed6-3d4b0f523bdb

Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

* fix(cli): polish test fixtures for /update command

- Remove unused _prompt_text_input from SimpleNamespace stub
- Use pytest.fail sentinel in managed-install guard test to catch unexpected modal invocations

Agent-Logs-Url: https://github.com/NousResearch/hermes-agent/sessions/f6da68cf-e7b1-4b7a-aed6-3d4b0f523bdb

Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

* chore: re-trigger CI after Copilot review fixes

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

---------

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: austinpickett <260188+austinpickett@users.noreply.github.com>

tests/hermes_cli/test_tui_resume_flow.py

@@ -523,6 +523,24 @@ def test_launch_tui_exports_model_provider_and_toolsets(monkeypatch, main_mod):
     assert env["NODE_ENV"] == "production"
 
 
+def test_launch_tui_exit_code_42_relaunches_update(monkeypatch, main_mod):
+    from unittest.mock import patch
+
+    monkeypatch.setattr(
+        main_mod,
+        "_make_tui_argv",
+        lambda tui_dir, tui_dev: (["node", "dist/entry.js"], Path(".")),
+    )
+    monkeypatch.setattr(main_mod.subprocess, "call", lambda *args, **kwargs: 42)
+
+    with patch("hermes_cli.relaunch.relaunch") as mock_relaunch:
+        with pytest.raises(SystemExit) as exc:
+            main_mod._launch_tui()
+
+    assert exc.value.code == 42
+    mock_relaunch.assert_called_once_with(["update"], preserve_inherited=False)
+
+
 def test_make_tui_argv_dev_prebuilds_hermes_ink(monkeypatch, main_mod, tmp_path):
     tui_dir = tmp_path / "ui-tui"
     tsx = tui_dir / "node_modules" / ".bin" / "tsx"