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>

.claude-plugin/marketplace.json

@@ -124,58 +124,6 @@
         "./agents/debug.md"
       ]
     },
-    {
-      "name": "advanced-ai-agents",
-      "source": "./advanced-ai-agents/",
-      "description": "Advanced AI agent for complex problem solving and deep analysis with GPT-5 integration",
-      "version": "1.0.0",
-      "author": {
-        "name": "Claude Code Dev Workflows",
-        "url": "https://github.com/cexll/myclaude"
-      },
-      "homepage": "https://github.com/cexll/myclaude",
-      "repository": "https://github.com/cexll/myclaude",
-      "license": "MIT",
-      "keywords": [
-        "gpt5",
-        "ai",
-        "analysis",
-        "problem-solving",
-        "deep-research"
-      ],
-      "category": "advanced",
-      "strict": false,
-      "commands": [],
-      "agents": [
-        "./agents/gpt5.md"
-      ]
-    },
-    {
-      "name": "requirements-clarity",
-      "source": "./requirements-clarity/",
-      "description": "Transforms vague requirements into actionable PRDs through systematic clarification with 100-point scoring system",
-      "version": "1.0.0",
-      "author": {
-        "name": "Claude Code Dev Workflows",
-        "url": "https://github.com/cexll/myclaude"
-      },
-      "homepage": "https://github.com/cexll/myclaude",
-      "repository": "https://github.com/cexll/myclaude",
-      "license": "MIT",
-      "keywords": [
-        "requirements",
-        "clarification",
-        "prd",
-        "specifications",
-        "quality-gates",
-        "requirements-engineering"
-      ],
-      "category": "essentials",
-      "strict": false,
-      "skills": [
-        "./skills/SKILL.md"
-      ]
-    },
     {
       "name": "codex-cli",
       "source": "./skills/codex/",