Add composite group routing

frontend/src/components/common/GroupSelector.vue

@@ -94,11 +94,11 @@ const filteredGroups = computed(() => {
     // antigravity 账户启用混合调度后，可选择 anthropic/gemini 分组
     if (props.platform === 'antigravity' && props.mixedScheduling) {
       result = result.filter(
-        (g) => g.platform === 'antigravity' || g.platform === 'anthropic' || g.platform === 'gemini'
+        (g) => g.platform === 'antigravity' || g.platform === 'anthropic' || g.platform === 'gemini' || g.platform === 'composite'
       )
     } else {
-      // 默认：只能选择同 platform 的分组
-      result = result.filter((g) => g.platform === props.platform)
+      // 默认：只能选择同 platform 的分组；composite 分组可接收任意具体平台账号
+      result = result.filter((g) => g.platform === props.platform || g.platform === 'composite')
     }
   }
   if (isSearchable.value && searchText.value) {

frontend/src/components/common/PlatformIcon.vue

@@ -25,6 +25,13 @@
       d="M9.27 15.29l7.978-5.897c.391-.29.95-.177 1.137.272.98 2.369.542 5.215-1.41 7.169-1.951 1.954-4.667 2.382-7.149 1.406l-2.711 1.257c3.889 2.661 8.611 2.003 11.562-.953 2.341-2.344 3.066-5.539 2.388-8.42l.006.007c-.983-4.232.242-5.924 2.75-9.383.06-.082.12-.164.179-.248l-3.301 3.305v-.01L9.267 15.292M7.623 16.723c-2.792-2.67-2.31-6.801.071-9.184 1.761-1.763 4.647-2.483 7.166-1.425l2.705-1.25a7.808 7.808 0 00-1.829-1A8.975 8.975 0 005.984 5.83c-2.533 2.536-3.33 6.436-1.962 9.764 1.022 2.487-.653 4.246-2.34 6.022-.599.63-1.199 1.259-1.682 1.925l7.62-6.815"
     />
   </svg>
+  <!-- Composite group icon -->
+  <svg v-else-if="platform === 'composite'" :class="sizeClass" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+    <circle cx="6" cy="12" r="3" />
+    <circle cx="18" cy="6" r="3" />
+    <circle cx="18" cy="18" r="3" />
+    <path stroke-linecap="round" stroke-linejoin="round" d="M8.7 10.7 15.3 7.3M8.7 13.3l6.6 3.4" />
+  </svg>
   <!-- Fallback: generic platform icon -->
   <svg v-else :class="sizeClass" fill="currentColor" viewBox="0 0 24 24">
     <path