chore: release v0.13.1

Bump version to 0.13.1 across root/backend/frontend and add the 0.13.1
CHANGELOG entry (COSS checkbox/table on the web, wallet-app home sheets).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "frontend",
-  "version": "0.13.0",
+  "version": "0.13.1",
   "private": true,
   "scripts": {
     "dev": "next dev",