chore(deps): remove deprecated subscriptions-transport-ws

The package is no longer maintained and was only reachable via the
Apollo WebSocketLink in app/plugins/apollo.ts. No Subscription type
exists in the schema and no subscription operations are defined, so the
ws split branch was dead code. Drop WebSocketLink, the split() routing,
and the direct dependency.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -58,8 +58,7 @@
     "graphql": "16.14.0",
     "graphql-tag": "2.12.6",
     "pinia": "3.0.4",
-    "pinia-plugin-persistedstate": "4.7.1",
-    "subscriptions-transport-ws": "0.11.0"
+    "pinia-plugin-persistedstate": "4.7.1"
   },
   "engines": {
     "node": "24"