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>

ui-tui/src/__tests__/createSlashHandler.test.ts

@@ -34,6 +34,21 @@ describe('createSlashHandler', () => {
     expect(ctx.gateway.gw.request).not.toHaveBeenCalled()
   })
 
+  it('handles /update locally and exits with code 42 via dieWithCode', () => {
+    vi.useFakeTimers()
+    const ctx = buildCtx()
+
+    expect(createSlashHandler(ctx)('/update')).toBe(true)
+    expect(ctx.gateway.gw.request).not.toHaveBeenCalled()
+    expect(ctx.transcript.sys).toHaveBeenCalledWith('exiting TUI to run update...')
+
+    // Advance past the 100ms setTimeout
+    vi.advanceTimersByTime(150)
+    expect(ctx.session.dieWithCode).toHaveBeenCalledWith(42)
+
+    vi.useRealTimers()
+  })
+
   it('routes /status to live session.status instead of slash worker', async () => {
     patchUiState({ sid: 'sid-abc' })
     const rpc = vi.fn(() => Promise.resolve({ output: 'Hermes TUI Status' }))
@@ -730,6 +745,7 @@ const buildComposer = () => ({
 const buildGateway = () => ({
   gw: {
     getLogTail: vi.fn(() => ''),
+    kill: vi.fn(),
     request: vi.fn(() => Promise.resolve({}))
   },
   rpc: vi.fn(() => Promise.resolve({}))
@@ -746,6 +762,7 @@ const buildLocal = () => ({
 const buildSession = () => ({
   closeSession: vi.fn(() => Promise.resolve(null)),
   die: vi.fn(),
+  dieWithCode: vi.fn(),
   guardBusySessionSwitch: vi.fn(() => false),
   newSession: vi.fn(),
   resetVisibleHistory: vi.fn(),