feat(caveman): full install — plugin + standalone hooks + MCP scaffold

Wires JuliusBrussee/caveman into the always-on tier alongside
security-guidance and superpowers. Caveman compresses Claude's output
tokens (~75%) by speaking like a caveman while keeping technical
substance. Three layers:

  1. Plugin (caveman@caveman, marketplace JuliusBrussee/caveman)
     — adds /caveman, /caveman-commit, /caveman-review, /caveman-stats,
       /caveman-help, /cavecrew, /compress + 3 cavecrew agents +
       SessionStart/UserPromptSubmit hooks from the plugin path.
  2. Standalone hooks (statusline + stats badge) deployed by
     caveman's own hooks/install.sh into ~/.claude/hooks/. Paths in
     settings.json normalized to ~/.claude/hooks/... so this user's
     home dir doesn't leak across machines.
  3. caveman-shrink MCP proxy — NOT auto-registered. The bare proxy
     fails health checks because it requires an upstream MCP server
     to wrap. install-plugins.sh STEP 5.5 prints a snippet showing how
     to register a wrapped entry (e.g. caveman-shrink-fs) when the user
     decides which upstream to compress.

New helper enable_plugin() for explicit always-on activation —
'claude plugin install' only copies into cache, doesn't write
enabledPlugins. Idempotent via Python json check.

doctor.sh adds detect_caveman / detect_caveman_hooks / detect_caveman_shrink
checks plus a 300t passive-cost adder. update-all.sh refreshes hook
files via the upstream installer's --force mode.

.gitignore covers caveman runtime files materialized into hooks/
because ~/.claude/hooks is symlinked to this repo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/detect-plugins.sh

@@ -66,6 +66,34 @@ detect_graphifyy() {
   command -v graphify &>/dev/null
 }
 
+detect_caveman() {
+  # Caveman — output-token compression via caveman-speak (marketplace plugin)
+  local cache_dir="$HOME/.claude/plugins/cache"
+  [ -d "$cache_dir" ] && compgen -G "$cache_dir"/*caveman* &>/dev/null
+}
+
+# True if a plugin is registered as enabled in settings.json's
+# enabledPlugins map. Filesystem only (no subprocess to claude CLI).
+# Argument is the full "name@marketplace" key.
+plugin_enabled() {
+  local key="$1"
+  [ -f "$HOME/.claude/settings.json" ] || return 1
+  grep -qE "\"${key}\"[[:space:]]*:[[:space:]]*true" "$HOME/.claude/settings.json"
+}
+
+detect_caveman_hooks() {
+  # Standalone hooks (statusline + stats) deployed by caveman hooks/install.sh
+  [ -f "$HOME/.claude/hooks/caveman-statusline.sh" ]
+}
+
+detect_caveman_shrink() {
+  # caveman-shrink is a proxy — only valid when registered with an
+  # upstream wrapper (e.g. caveman-shrink-fs:, caveman-shrink-github:).
+  # Bare 'caveman-shrink:' fails health checks and is treated as missing.
+  command -v claude &>/dev/null \
+    && claude mcp list 2>/dev/null | grep -q '^caveman-shrink-'
+}
+
 
 # --- Plan detection ---