Rewrite as uv-based Flask web app with Dockerfile

- Flask dashboard with Plotly charts (stores, monthly, hourly, weekday, heatmap)
- Spotify Wrapped-style summary with year dropdown and inflation toggle
- CSV upload flow (ephemeral, no storage)
- Homepage with upload and saved data options
- Import script for loading CSVs into SQLite
- Dockerized with gunicorn for production

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

.gitignore

@@ -1,5 +1,9 @@
 # who the fuck forgets to add this smh
 
-
 env/
-venv/
+venv/
+.venv/
+__pycache__/
+*.pyc
+.DS_Store
+*.db.bak