feat: implement modular installation system

引入模块化安装系统,支持可配置的工作流组合:

核心改进:
- .claude-plugin/marketplace.json: 移除废弃模块引用,精简插件清单
- .gitignore: 添加 Python 开发环境忽略项(.venv, __pycache__, .coverage)
- Makefile: 标记 make install 为 LEGACY,推荐使用 install.py
- install.sh: codex-wrapper 安装脚本,添加到 PATH

新架构使用 config.json 控制模块启用/禁用,支持:
- 选择性安装工作流(dev/bmad/requirements/essentials)
- 声明式操作定义(merge_dir/copy_file/run_command)
- 版本化配置管理

迁移路径: make install -> python3 install.py --install-dir ~/.claude

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Makefile

@@ -7,10 +7,12 @@
 help:
 	@echo "Claude Code Multi-Agent Workflow - Quick Deployment"
 	@echo ""
+	@echo "Recommended installation: python3 install.py --install-dir ~/.claude"
+	@echo ""
 	@echo "Usage: make [target]"
 	@echo ""
 	@echo "Targets:"
-	@echo "  install              - Install all configurations to Claude Code"
+	@echo "  install              - LEGACY: install all configurations (prefer install.py)"
 	@echo "  deploy-bmad          - Deploy BMAD workflow (bmad-pilot)"
 	@echo "  deploy-requirements  - Deploy Requirements workflow (requirements-pilot)"
 	@echo "  deploy-essentials    - Deploy Development Essentials workflow"
@@ -36,6 +38,8 @@ OUTPUT_STYLES_DIR = output-styles
 
 # Install all configurations
 install: deploy-all
+	@echo "⚠️  LEGACY PATH: make install will be removed in future versions."
+	@echo "    Prefer: python3 install.py --install-dir ~/.claude"
 	@echo "✅ Installation complete!"
 
 # Deploy BMAD workflow
@@ -140,4 +144,4 @@ all: deploy-all
 # Version info
 version:
 	@echo "Claude Code Multi-Agent Workflow System v3.1"
-	@echo "BMAD + Requirements-Driven Development"
+	@echo "BMAD + Requirements-Driven Development"