v1.8.0 - FastAPI Backend and Data Caching

1. FastAPI Backend - Added API endpoints for listing launches, retrieving the next launch, fetching launch details, and checking service health.
2. Normalized Launch Data - Converted Launch Library 2 records into a consistent launch model.
3. 10-Minute Cache - Cached upstream data for 10 minutes to reduce API requests and extend free-tier usage.
4. Single-Flight Refresh - Added a lock to prevent concurrent requests from triggering duplicate data refreshes.
5. Stale Data Fallback - Kept serving the last successful data with a stale flag when the upstream API fails.
6. Refresh Backoff - Added a 60-second cooldown after a failed refresh to avoid repeated requests.
7. Frontend API Integration - Switched the frontend to fetch launches from /api/launches and use normalized fields.
8. Local Development Mode - Added local run instructions and a development mode that serves the frontend directly from the API.

Published - v1.8.0 is now available on GitHub.