refactor: migrate CRM data layer from manual gqlFetch to Apollo Client

Replace custom gqlFetch() with proper Apollo useQuery/useMutation hooks
powered by codegen-generated TypedDocumentNode types. Key changes:

- Add GraphQL SDL schema file and codegen config for typescript-vue-apollo
- Replace all 28 raw .graphql imports with generated typed documents
- Add 12 useQuery() hooks with cache-and-network fetch policy
- Add 17 useMutation() hooks with surgical refetchQueries per mutation
- Optimistic cache update for setContactInboxHidden (instant archive UX)
- Fix contact list subtitle: show lastText instead of channel name
- Migrate login page from gqlFetch to useMutation
- WebSocket realtime now calls Apollo refetch instead of full data reload

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/app/components/workspace/communications/CrmCommunicationsListSidebar.vue

@@ -146,7 +146,7 @@ function onSearchInput(event: Event) {
               <span class="shrink-0 text-[10px] text-base-content/55">{{ formatThreadTime(thread.lastAt) }}</span>
             </div>
             <p class="mt-0.5 min-w-0 truncate text-[11px] text-base-content/75">
-              {{ threadChannelLabel(thread) }}
+              {{ thread.lastText || threadChannelLabel(thread) }}
             </p>
           </div>
         </div>