feat(web): inset token silhouette by 2px

Pass a negative offset through traceImage so the traced token shape
sits slightly inside the artwork, hiding the anti-aliased fringe.

apps/web/src/api.ts

@@ -20,13 +20,17 @@ export function searchWorkshop(q: string, page = 1): Promise<SearchResult> {
 
 /**
  * Trace an image into a vector shape, BSON-deserializing the proxy response.
- * `mode` controls how the region is derived (`alpha`, `bw`, `color`).
+ * `mode` controls how the region is derived (`alpha`, `bw`, `color`); a
+ * non-zero `offset` insets (negative) or outsets (positive) the shape in
+ * pixels.
  */
 export async function traceImage(
   url: string,
   mode: 'alpha' | 'bw' | 'color' = 'alpha',
+  offset?: number,
 ): Promise<TraceResult> {
   const params = new URLSearchParams({ url, mode });
+  if (offset !== undefined) params.set('offset', String(offset));
   const res = await fetch(`${BASE}/trace?${params.toString()}`);
   if (!res.ok) {
     const body = (await res.json().catch(() => null)) as { error?: string } | null;

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

@@ -14,6 +14,9 @@ import { assetUrl } from './assetUrl';
 
 const TOKEN_SIZE = 1.8;
 
+/** How far (in trace pixels) the token silhouette is inset from the artwork. */
+const TRACE_INSET = 2;
+
 /**
  * A token: a short extruded shape with the texture on its top face. Uses
  * `CustomImage.ImageURL` (falling back to `ImageSecondaryURL`), with a neutral
@@ -46,7 +49,7 @@ function TokenMesh({ url, thickness }: { url?: string; thickness: number }) {
     let cancelled = false;
     setTrace(null);
     if (!url) return;
-    traceImage(url, 'alpha')
+    traceImage(url, 'alpha', -TRACE_INSET)
       .then((result) => {
         if (!cancelled && result.shape) {
           setTrace({