feat: initialize project structure and configuration

- Create backend directory structure (app/models, app/schemas, app/services, app/api, app/tasks, tests)
- Create frontend directory structure (src/router, src/views, src/components, src/api, src/stores)
- Create data directories (ssh_keys, repos)
- Add requirements.txt with FastAPI, SQLAlchemy, Pydantic, and testing dependencies
- Add frontend package.json with Vue 3, Vue Router, Pinia, and Element Plus
- Add .env.example with configuration template
- Add .gitignore for Python, data directories, and frontend
- Add pytest conftest.py with test fixtures for database and environment

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

.gitignore

@@ -0,0 +1,30 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+env/
+venv/
+.venv/
+
+# 数据
+data/
+*.db
+*.db-journal
+
+# 环境变量
+.env
+
+# IDE
+.idea/
+.vscode/
+*.swp
+
+# 前端
+frontend/node_modules/
+frontend/dist/
+frontend/.vite/
+
+# 日志
+*.log