chore(deps): remove deprecated subscriptions-transport-ws (#2922)

Removes the deprecated `subscriptions-transport-ws` package (Renovate dependency dashboard #49).

The package is unmaintained and was only reachable through the Apollo `WebSocketLink` in `app/plugins/apollo.ts`. The schema has no `Subscription` type and no subscription operations are defined, so the ws `split()` branch was dead code.

- Drop `WebSocketLink`, the `split()` routing, `getMainDefinition`, and `wsUrl` from `app/plugins/apollo.ts`
- Remove the direct `subscriptions-transport-ws` dependency

Verified with `npm run build` (green) and eslint (clean).

Note: the package lingers in the lockfile as an optional peer dep of `@apollo/client` v3; it disappears with the Apollo Client v4 upgrade, which removes `@apollo/client/link/ws` entirely.

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

Reviewed-on: #2922

app/plugins/apollo.ts

@@ -1,7 +1,5 @@
-import { ApolloClient, ApolloLink, createHttpLink, from, InMemoryCache, split } from '@apollo/client/core'
+import { ApolloClient, ApolloLink, createHttpLink, from, InMemoryCache } from '@apollo/client/core'
 import { setContext } from '@apollo/client/link/context'
-import { WebSocketLink } from '@apollo/client/link/ws'
-import { getMainDefinition } from '@apollo/client/utilities'
 import type { GetTokenSilentlyOptions } from '@auth0/auth0-spa-js'
 import type { Auth0VueClient } from '@auth0/auth0-vue'
 import { SpanKind, TraceFlags } from '@opentelemetry/api'
@@ -11,7 +9,6 @@ import { defineNuxtPlugin, useNuxtApp } from '#app'
 import { envConfig } from '~/utils/environment'
 
 const apiUrl = envConfig(window.location.hostname).apiUrl
-const wsUrl = apiUrl.replace(/^http/, 'ws')
 
 const cache = new InMemoryCache({
   typePolicies: {
@@ -42,19 +39,6 @@ const httpLink = createHttpLink({
   uri: apiUrl,
 })
 
-const wsLink = new WebSocketLink({
-  uri: wsUrl,
-  options: {
-    reconnect: true,
-    lazy: true,
-    connectionParams: () => {
-      return getToken({}).then((token) => ({
-        authToken: token,
-      }))
-    },
-  },
-})
-
 const authLink = setContext(async (_, { headers }) => {
   return await getToken({}).then((token) => ({
     headers: {
@@ -86,17 +70,7 @@ const createSpanLink = new ApolloLink((operation, forward) => {
 const link =
   from([
     createSpanLink,
-    split(
-      ({ query }) => {
-        const definition = getMainDefinition(query)
-        return (
-          definition.kind === 'OperationDefinition' &&
-            definition.operation === 'subscription'
-        )
-      },
-      authLink.concat(wsLink),
-      authLink.concat(httpLink),
-    ),
+    authLink.concat(httpLink),
   ])
 
 const instance = new ApolloClient({