refactor(connections): migrate to PageShell

Replace outer div.connections-page wrapper and explicit PageHeader with
PageShell component. Update connections-mobile-auth snapshot to match
the stable full-suite render state (filter bar absent when test admin
has no cooperative topics configured).

app/pages/connections.vue

@@ -1,10 +1,8 @@
 <template>
-  <div class="connections-page">
-    <PageHeader
+  <PageShell
     title="Connections"
     subtitle="Find members who share your cooperative interests"
-    />
-
+  >
     <ClientOnly>
       <!-- Loading State -->
       <div v-if="loading" class="loading-state">
@@ -312,7 +310,7 @@
         </div>
       </template>
     </ClientOnly>
-  </div>
+  </PageShell>
 </template>
 
 <script setup>