feat: Initialize FastAPI application with Azure authentication and transaction management

- Added .env.example for environment variable configuration.
- Created app initialization files and core settings management.
- Implemented API routers for reporting and transaction endpoints.
- Developed transaction management service with CRUD operations.
- Integrated Azure OAuth for user authentication.
- Designed dashboard view with transaction filtering and display.
- Added Swagger UI documentation with custom dark theme.
- Created static and template files for frontend styling and layout.

app/api/__init__.py

@@ -0,0 +1,4 @@
+from app.api.reporting import router as reporting_router
+from app.api.transactions import router as transactions_router
+
+__all__ = ["reporting_router", "transactions_router"]