refactor: share trace, error boundary, and proxy http helpers

Lift the trace-to-shape geometry into @tts/mesh (traceToShape/
traceToUvBounds), parameterized by scale so the web token viewer and
@tts/tabletop share one implementation. Move the CORS proxy HTTP helpers
(assetUrl, resolveAssetUrl, traceImage) into a new @tts/http package, and
make @tts/tabletop's ErrorBoundary the single source used by the web app.

This removes the duplicated ErrorBoundary, assetUrl, tabletopHttp, and
trace-to-shape code from apps/web and packages/tabletop.

apps/web/src/components/viewers/CardViewer.tsx

@@ -8,7 +8,7 @@ import {
   type ExtrudedGeometry,
 } from '@tts/mesh';
 import Scene from './Scene';
-import { assetUrl } from './assetUrl';
+import { assetUrl } from '@tts/http';
 import { cardAspect, resolveCardConfig, spriteUv } from './cardResolution';
 import { flipTexture } from './flipTexture';
 import { getSharedGeometry, objectTint, tintedColor } from './sharedResources';