Add web UX with dashboard, import wizard, backup management

- SPA frontend (static/index.html): 4-step wizard flow
  (Upload → Review → Import → Report) + Dashboard bar + Backup UI
- FastAPI server (server.py) with 14 API endpoints
- New endpoints: /api/status, /api/backups, /api/backup/restore
- Updated README with web UX usage
- Added web deps: fastapi, uvicorn, python-multipart

requirements.txt

@@ -11,3 +11,8 @@ httpx>=0.24
 # CLI
 rich>=13.0
 click>=8.0
+
+# Web UX
+fastapi>=0.100
+uvicorn>=0.20
+python-multipart>=0.0.6