3 pages (market, PRINZIP drilldown, developers leaderboard) on top of
existing v_developer_full_metrics + domrf_realization views. ECharts on
the frontend, FastAPI router /api/v1/analytics on the backend.
- empty_buildings: dict → dict[str, Any] (mypy strict needs type args)
- drop unused `# type: ignore[arg-type]` on strategy= (mypy now narrows
the loop variable to Literal[...] from a tuple of literals)
