fix(install): register plugin in installed_plugins.json with commands/ layout

Claude Code requires skill files in commands/ subdirectory and a registration
entry in installed_plugins.json. The previous install.sh just copied files to
a bare directory which Claude Code never discovered.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

install.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-# install.sh — install the ralph-workplan skill into ~/.claude/plugins/
+# install.sh — install the ralph-workplan skill into Claude Code's plugin system
 #
 # Usage:
 #   ./install.sh              # install
@@ -8,32 +8,59 @@
 set -euo pipefail
 
 PLUGIN_NAME="ralph-workplan"
-PLUGIN_SRC="$(cd "$(dirname "$0")/plugin" && pwd)"
-PLUGIN_DEST="${HOME}/.claude/plugins/${PLUGIN_NAME}"
+REPO_DIR="$(cd "$(dirname "$0")" && pwd)"
+PLUGINS_DIR="${HOME}/.claude/plugins"
+INSTALL_PATH="${PLUGINS_DIR}/cache/local/${PLUGIN_NAME}"
+REGISTRY="${PLUGINS_DIR}/installed_plugins.json"
 
+# ── Uninstall ──────────────────────────────────────────────────────────────────
 if [[ "${1:-}" == "--uninstall" ]]; then
-  if [[ -d "$PLUGIN_DEST" ]]; then
-    rm -rf "$PLUGIN_DEST"
-    echo "✅ Uninstalled: $PLUGIN_DEST"
-  else
-    echo "ℹ️  Not installed (nothing to remove)"
+  if [[ -d "$INSTALL_PATH" ]]; then
+    rm -rf "$INSTALL_PATH"
+    echo "Removed: $INSTALL_PATH"
   fi
+  # Remove from installed_plugins.json
+  if [[ -f "$REGISTRY" ]]; then
+    python3 - "$REGISTRY" "$PLUGIN_NAME" <<'PY'
+import json, sys
+path, name = sys.argv[1], sys.argv[2]
+d = json.load(open(path))
+d.setdefault("plugins", {}).pop(name, None)
+json.dump(d, open(path, "w"), indent=2)
+print(f"Removed '{name}' from {path}")
+PY
+  fi
+  echo "✅ Uninstalled: $PLUGIN_NAME"
+  echo "   Restart Claude Code to apply."
   exit 0
 fi
 
-# Install
-mkdir -p "${PLUGIN_DEST}/scripts"
+# ── Install ────────────────────────────────────────────────────────────────────
+mkdir -p "${INSTALL_PATH}/commands"
+mkdir -p "${INSTALL_PATH}/scripts"
 
-cp "${PLUGIN_SRC}/ralph-workplan.md"       "${PLUGIN_DEST}/ralph-workplan.md"
-cp "${PLUGIN_SRC}/scripts/check-done.sh"   "${PLUGIN_DEST}/scripts/check-done.sh"
-cp "${PLUGIN_SRC}/scripts/setup.sh"        "${PLUGIN_DEST}/scripts/setup.sh"
+# Skill file goes in commands/ — that's where Claude Code looks
+cp "${REPO_DIR}/plugin/ralph-workplan.md"     "${INSTALL_PATH}/commands/ralph-workplan.md"
+cp "${REPO_DIR}/plugin/scripts/check-done.sh" "${INSTALL_PATH}/scripts/check-done.sh"
+cp "${REPO_DIR}/plugin/scripts/setup.sh"      "${INSTALL_PATH}/scripts/setup.sh"
 
-chmod +x "${PLUGIN_DEST}/scripts/check-done.sh"
-chmod +x "${PLUGIN_DEST}/scripts/setup.sh"
+chmod +x "${INSTALL_PATH}/scripts/check-done.sh"
+chmod +x "${INSTALL_PATH}/scripts/setup.sh"
 
-echo "✅ Installed: $PLUGIN_DEST"
-echo ""
-echo "   Skill:   /ralph-workplan <workplan-file> [--max-iterations N]"
-echo "   Spec:    $(cd "$(dirname "$0")" && pwd)/workplan-spec.md"
+# Register in installed_plugins.json so Claude Code discovers the plugin
+python3 - "$REGISTRY" "$PLUGIN_NAME" "$INSTALL_PATH" <<'PY'
+import json, sys
+path, name, install_path = sys.argv[1], sys.argv[2], sys.argv[3]
+try:
+    d = json.load(open(path))
+except (FileNotFoundError, json.JSONDecodeError):
+    d = {"version": 2, "plugins": {}}
+d.setdefault("plugins", {})[name] = [{"scope": "user", "installPath": install_path}]
+json.dump(d, open(path, "w"), indent=2)
+PY
+
+echo "✅ Installed: $PLUGIN_NAME"
+echo "   Path:  $INSTALL_PATH"
+echo "   Skill: /ralph-workplan <workplan-file> [--max-iterations N]"
 echo ""
 echo "   Restart Claude Code for the skill to appear."