1.0.151

mike: add market stats to store cards — city-wide pricing + demand data

Default stats view now shows two rows:
- Row 1 (your store): sold/day, revenue, margin, stock, revenue sparkline
- Row 2 (market): avg market price, cheapest supply, city demand/day, price sparkline
- Edit mode shows market hint line (avg price · cheapest · demand)

Uses getPriceHistory API for city-wide market data alongside getBuildingSales for store data.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>