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>

install.sh

@@ -125,6 +125,14 @@ PI_SEARCH_PATHS=(
     "$HOME/bin/pi"
 )
 
+# Grok CLI search paths (from src/utils/grok-cli-resolver.ts)
+GROK_SEARCH_PATHS=(
+    "$HOME/.grok/bin/grok"
+    "$HOME/.local/bin/grok"
+    "/usr/local/bin/grok"
+    "$HOME/bin/grok"
+)
+
 # Antigravity CLI search paths (from src/utils/antigravity-cli-resolver.ts)
 ANTIGRAVITY_SEARCH_PATHS=(
     "$HOME/.local/bin/agy"
@@ -569,6 +577,37 @@ get_pi_path() {
     done
 }
 
+# `grok` has known squatters too (the unrelated @vibe-kit/grok-cli), so the
+# server-side resolver additionally probes `grok --version`. Detection here only
+# feeds the "you have no AI CLI" hint, so a plain executable test is enough.
+check_grok() {
+    if command -v grok &>/dev/null; then
+        return 0
+    fi
+
+    for path in "${GROK_SEARCH_PATHS[@]}"; do
+        if [[ -x "$path" ]]; then
+            return 0
+        fi
+    done
+
+    return 1
+}
+
+get_grok_path() {
+    if command -v grok &>/dev/null; then
+        command -v grok
+        return
+    fi
+
+    for path in "${GROK_SEARCH_PATHS[@]}"; do
+        if [[ -x "$path" ]]; then
+            echo "$path"
+            return
+        fi
+    done
+}
+
 check_cloudflared() {
     # Check ~/.local/bin first (matches tunnel-manager.ts resolution order)
     if [[ -x "$HOME/.local/bin/cloudflared" ]]; then
@@ -2083,6 +2122,7 @@ main() {
     local has_gemini=false
     local has_antigravity=false
     local has_pi=false
+    local has_grok=false
 
     info "Checking AI CLI tools..."
     if check_claude; then
@@ -2109,17 +2149,21 @@ main() {
         has_pi=true
         success "Pi CLI found at $(get_pi_path)"
     fi
+    if check_grok; then
+        has_grok=true
+        success "Grok CLI found at $(get_grok_path)"
+    fi
 
-    if [[ "$has_claude" == "false" && "$has_opencode" == "false" && "$has_codex" == "false" && "$has_gemini" == "false" && "$has_antigravity" == "false" && "$has_pi" == "false" ]]; then
+    if [[ "$has_claude" == "false" && "$has_opencode" == "false" && "$has_codex" == "false" && "$has_gemini" == "false" && "$has_antigravity" == "false" && "$has_pi" == "false" && "$has_grok" == "false" ]]; then
         echo ""
-        warn "No AI CLI found. Codeman needs at least one: Claude Code, OpenCode, Codex, Antigravity, Gemini, or Pi."
+        warn "No AI CLI found. Codeman needs at least one: Claude Code, OpenCode, Codex, Antigravity, Gemini, Pi, or Grok."
         headless_guard "install an AI CLI (curl | bash from its vendor)"
         echo ""
         echo -e "  ${BOLD}Which AI CLI would you like to install?${NC}"
         echo -e "    ${CYAN}1)${NC} Claude Code  (Anthropic)"
         echo -e "    ${CYAN}2)${NC} OpenCode     (open-source)"
         echo -e "    ${CYAN}3)${NC} Both"
-        echo -e "    ${CYAN}4)${NC} Skip         (I'll install one myself, e.g. Codex, Antigravity or Pi)"
+        echo -e "    ${CYAN}4)${NC} Skip         (I'll install one myself, e.g. Codex, Antigravity, Pi or Grok)"
         echo ""
 
         local cli_choice=""
@@ -2167,6 +2211,7 @@ main() {
             info "Install one later, e.g.: npm install -g @openai/codex                          (Codex)"
             info "                    or: curl -fsSL https://antigravity.google/cli/install.sh | bash  (Antigravity)"
             info "                    or: npm install -g --ignore-scripts @earendil-works/pi-coding-agent   (Pi)"
+            info "                    or: curl -fsSL https://x.ai/cli/install.sh | bash                     (Grok)"
         elif [[ "$has_claude" == "false" ]] && [[ "$has_opencode" == "false" ]]; then
             die "The selected AI CLI failed to install. Install one manually and re-run the installer."
         fi
@@ -2467,13 +2512,14 @@ main() {
     echo -e "    https://github.com/Ark0N/Codeman"
     echo ""
 
-    if ! check_claude && ! check_opencode && ! check_codex && ! check_gemini && ! check_antigravity && ! check_pi; then
+    if ! check_claude && ! check_opencode && ! check_codex && ! check_gemini && ! check_antigravity && ! check_pi && ! check_grok; then
         echo -e "  ${YELLOW}${BOLD}Reminder:${NC} Install at least one AI CLI to start using Codeman:"
         echo -e "    ${CYAN}curl -fsSL https://claude.ai/install.sh | bash${NC}                # Claude Code"
         echo -e "    ${CYAN}curl -fsSL https://opencode.ai/install | bash${NC}                 # OpenCode"
         echo -e "    ${CYAN}npm install -g @openai/codex${NC}                                  # Codex"
         echo -e "    ${CYAN}curl -fsSL https://antigravity.google/cli/install.sh | bash${NC}   # Antigravity"
         echo -e "    ${CYAN}npm install -g --ignore-scripts @earendil-works/pi-coding-agent${NC}  # Pi"
+        echo -e "    ${CYAN}curl -fsSL https://x.ai/cli/install.sh | bash${NC}                 # Grok"
         echo ""
     fi