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>

backend/requirements.txt

@@ -0,0 +1,14 @@
+fastapi==0.109.0
+uvicorn[standard]==0.27.0
+sqlalchemy==2.0.25
+pydantic==2.5.3
+pydantic-settings==2.1.0
+python-multipart==0.0.6
+apscheduler==3.10.4
+paramiko==3.4.0
+gitpython==3.1.40
+cryptography==41.0.7
+requests==2.31.0
+pytest==7.4.4
+pytest-asyncio==0.23.3
+httpx==0.26.0