v0.6.1 — Minesweeper scales to the level

Follow-up to v0.6.0.

Cell size now scales with the level. A fixed cell made Beginner a postage stamp floating in a large modal while Expert sprawled — 9 columns and 30 columns cannot share one number. Cells scale inversely so the window stays roughly constant: Beginner 9×48, Intermediate 16×32, Expert 30×24. Mine and flag glyphs scale with the cell instead of staying 14px on a 48px tile.

Requires an Agent Code build with the frame shrink fix. The host measured #root.scrollWidth for the modal width, but #root is width: 100% and scrollWidth is never smaller than clientWidth — so the reported width was always at least the current iframe width. The modal could grow and never shrink, which left it frozen at the previous game's width when you switched to a narrower one. Fixed host-side in frameDocument.ts; without it, switching from Blackjack to Minesweeper will still show the old oversized modal.