feat(grok): add Grok Build (xAI) as a seventh CLI run mode

SessionMode gains 'grok', a first-class backend alongside Claude Code,
shell, OpenCode, Codex, Gemini, Antigravity and Pi: its own PTY, tmux
session, charcoal tab identity ('gk' badge), welcome button, run-mode
entry, cron agentType, Docker and remote-SSH command defaults, and
clone-repo Brain option. Flag surface verified live against grok 1.0.5.

Grok mixes two existing shapes and the wiring follows from that:

- Codex-shaped on permissions: the bypass switch is GrokConfig.alwaysApprove
  (--always-approve, grok's bypassPermissions mode; config-level deny rules
  still apply on top). The Run button sends it true, like runAntigravity(),
  and clampExternalCliBypassForOwner() puts grok in the only-if-sent branch:
  a bare grok spawn is grok's own ask-mode default, which is already safe,
  so only a sent config needs the flag forced off. Cron needs nothing for
  the same reason.
- OpenCode-shaped on rendering: grok is a fullscreen alternate-screen TUI
  with mouse support, so it stays OUT of isAltScreenStripMode() and lands
  on the narrow tmux-attach strip and the 'buffer' local-echo fallthrough
  (unmeasured against an authenticated composer; documented fallback is the
  'off' branch).
- Pi-shaped on resolution: 'grok' has npm squatters (@vibe-kit/grok-cli
  also installs a grok bin), so grok-cli-resolver.ts version-probes every
  candidate (grok --version, killSignal SIGKILL, VITEST-gated) and
  GET /api/grok/status surfaces path AND version; GROK_VERSION_REGEX is
  shared with the dependency registry so doctor and run mode cannot drift.

Env allowlist gains GROK_* plus the XAI_* vendor namespace (XAI_API_KEY is
grok's documented headless auth var), the same narrow-vendor reasoning as
GOOGLE_* for gemini. Resume is id-regexed on purpose: grok's own --resume
also matches session titles, which are arbitrary user strings that must
never reach the bash -c spawn line.

Docker: grok is not on npm, so the agent image installs it in its own step
(xAI's installer has no --dir override; the binary is copied to
/usr/local/bin and root's ~/.grok dropped in the same layer), and
credentials are seeded per-file (auth.json, config.toml, pager.toml; the
dir also holds sessions/, memory/ and the ~160MB binary). Remote SSH routes
through the login-shell wrapper like the other agent CLIs.

Verified end to end on an isolated CODEMAN_INSTANCE with grok 1.0.5
installed: /api/grok/status resolves and reports the probed version,
quick-start spawns a pane whose command line ends in 'grok
--always-approve', the real TUI renders (OAuth device screen on an
unauthenticated box), and grokConfig round-trips through state.json.
Docs: docs/grok-integration.md (user guide) + docs/grok-integration-plan.md
(decisions, verification record, follow-ups).

Tests: test/grok-mode.test.ts, test/grok-cli-resolver.test.ts, plus
extended clamp/system-routes/render-index-html/run-mode-ui/mobile-overview/
local-echo-gating coverage. npm test (the CI gate) green: 5910 tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skills/codeman/reference/endpoints.md

@@ -237,7 +237,7 @@ minutes, never retry the credential.
 flushed slightly *after* the `stop` hook fires, so a read taken the instant the wait
 returns is too early (verified live: empty on the first call, full prose seconds later).
 It is also `""` before the worker's first completed turn, and permanently `""` for
-`shell`, `opencode`, `gemini`, `antigravity` and `pi`, which write no Claude transcript.
+`shell`, `opencode`, `gemini`, `antigravity`, `pi` and `grok`, which write no Claude transcript.
 
 **Fix** Poll it, bounded (10 tries, 1 s apart). If it is still empty on a hook-less mode,
 that is expected, not a failure: read `terminal?tail=` and strip ANSI instead.
@@ -336,14 +336,14 @@ ESC=$(printf '\033')
 
 `POST /api/v1/quick-start` body (all optional):
 `{"caseName":"worker-1","mode":"claude","sessionName":"w9-worker","effort":"high"}`
-,  `mode` ∈ `claude|shell|opencode|codex|gemini|antigravity|pi`; response is
+,  `mode` ∈ `claude|shell|opencode|codex|gemini|antigravity|pi|grok`; response is
 `.data.{sessionId, caseName, casePath}`. Creates the case directory (a real directory
 on the user's disk) if missing, do not retry it in a loop, and remember the name.
 
 ⚠️ A `mode` whose CLI is **not installed on the server** fails the spawn with
 `OPERATION_FAILED`; it never falls back to claude. Probe first whenever you did not pick
 the mode yourself: `GET /api/v1/claude/status`, `GET /api/v1/opencode/status`,
-`GET /api/v1/codex/status`, `GET /api/v1/gemini/status`, `GET /api/v1/antigravity/status`
+`GET /api/v1/codex/status`, `GET /api/v1/gemini/status`, `GET /api/v1/antigravity/status`, `GET /api/v1/grok/status`
 and `GET /api/v1/pi/status` each return `.data.{available, path}` (no session needed).
 Pi's also carries `.data.version`, because `pi` is a short generic name that an unrelated
 binary on `$PATH` can shadow: the resolver rejects one whose `--version` is not
@@ -463,7 +463,7 @@ Quirks that will bite you:
 - ⚠️ **`active-tools` proves presence, never absence.** It is fed by the BashToolParser,
   which reads Claude's rendered `● Bash(…)` lines, and `_processExpensiveParsers`
   returns early for every external CLI mode (`session.ts:2136`), so it is permanently
-  `[]` on `opencode`/`codex`/`gemini`/`antigravity`/`pi`. ⚠️ **`shell` is NOT one of those**
+  `[]` on `opencode`/`codex`/`gemini`/`antigravity`/`pi`/`grok`. ⚠️ **`shell` is NOT one of those**
   (`isExternalCliMode`, `session.ts:165-167`, lists only those five), so the parser does
   run on a shell worker, and `TEXT_COMMAND_PATTERN` (`bash-tool-parser.ts:88`) matches
   bare `tail|cat|head|less|grep|watch|multitail <path>` lines with no `● Bash(` wrapper: