Implement FastAPI backend and Vue 3 frontend for Lowkey Backtest UI

- Added FastAPI backend with core API endpoints for strategies, backtests, and data management.
- Introduced Vue 3 frontend with a dark theme, enabling users to run backtests, adjust parameters, and compare results.
- Implemented Pydantic schemas for request/response validation and SQLAlchemy models for database interactions.
- Enhanced project structure with dedicated modules for services, routers, and components.
- Updated dependencies in `pyproject.toml` and `frontend/package.json` to include FastAPI, SQLAlchemy, and Vue-related packages.
- Improved `.gitignore` to exclude unnecessary files and directories.

pyproject.toml

@@ -15,6 +15,10 @@ dependencies = [
     "plotly>=5.24.0",
     "requests>=2.32.5",
     "python-dotenv>=1.2.1",
+    # API dependencies
+    "fastapi>=0.115.0",
+    "uvicorn[standard]>=0.34.0",
+    "sqlalchemy>=2.0.0",
 ]
 
 [project.optional-dependencies]