The studio front door loads a full-size screenshot per app tile where a 200x125 thumb already exists #320

studioLanding (src/web/pages/site.ts) now picks each app tile's picture the same way lookNow already does: the dedicated thumb (200×125) when one exists, falling back to the desktop shot (1280×800) for looks taken before thumbs existed — width/height attributes always match the kind actually shown, so nothing shifts. The selection rule (pictured) is exported from src/web/pages/looks.ts rather than duplicated, and the landing still reads looks in the one grouped looksForApps call it always did — no new query per tile.

Two tests in test/studio.test.ts cover it: one with both a thumb and a desktop look present, asserting the tile's src ends in /thumb.png at 200×125 (verified this fails on the pre-fix code); one with only a pre-thumb desktop look, asserting the tile still renders at 1280×800.

I checked .app-tile-look's CSS (width:100%; height:auto in a minmax(220px,1fr) grid) — most rows keep tiles near 220–260px wide, so a 200px thumb is only mildly upscaled; the worst case is a single-column mobile layout (~300–330px), a ~1.5× stretch, visibly softer than the desktop source but not mush. Left as-is per the issue's own guidance — if it reads as too soft in review, the fix is a 2×thumb kind, which is a separate ask since it needs a new LookKind and capture size, not a CSS change here.

bun x tsc --noEmit is clean; bun test test/studio.test.ts passes 157/157. I also ran test/looks.test.ts, test/apps.test.ts, test/board.test.ts: one pre-existing failure in looks.test.ts (confirmed present on unmodified main too, unrelated to this change — a pull-page look-thumb assertion).

Closes #287