Bump FigCraft downloads to 0.5.1 (#137)

Points the FigCraft download buttons on `/apps/figcraft` at
[v0.5.1](https://github.com/storytold/figcraft/releases/tag/v0.5.1) (was
0.4.0). The release ships the same file set, so only the version
changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

frontend/apps/artcraft-website-next/src/lib/crafting-app-releases.ts

@@ -221,7 +221,7 @@ export const CRAFT_APP_RELEASES: Record<CraftAppSlug, CraftRelease | null> = {
   pdfcraft: craftRelease("0.6.0"),
   effectcraft: craftRelease("0.8.0"),
   designcraft: craftRelease("0.6.0"),
-  figcraft: craftRelease("0.4.0"),
+  figcraft: craftRelease("0.5.1"),
   wordcraft: craftRelease("0.5.0"),
   soundcraft: craftRelease("0.5.0"),
   deckcraft: craftRelease("0.5.0"),