feat(admin): 分组管理新增容量列（并发/会话/RPM 实时聚合）

复用 GroupCapacityService，在 admin 分组列表中添加容量列，
显示每个分组的实时并发/会话/RPM 使用量和上限。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/common/GroupCapacityBadge.vue

@@ -0,0 +1,84 @@
+<template>
+  <div class="flex flex-col gap-1">
+    <!-- 并发槽位 -->
+    <div class="flex items-center gap-1">
+      <span
+        :class="[
+          'inline-flex items-center gap-1 rounded-md px-1.5 py-0.5 text-[10px] font-medium',
+          capacityClass(concurrencyUsed, concurrencyMax)
+        ]"
+      >
+        <svg class="h-2.5 w-2.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+          <path stroke-linecap="round" stroke-linejoin="round" d="M3.75 6A2.25 2.25 0 016 3.75h2.25A2.25 2.25 0 0110.5 6v2.25a2.25 2.25 0 01-2.25 2.25H6a2.25 2.25 0 01-2.25-2.25V6zM3.75 15.75A2.25 2.25 0 016 13.5h2.25a2.25 2.25 0 012.25 2.25V18a2.25 2.25 0 01-2.25 2.25H6A2.25 2.25 0 013.75 18v-2.25zM13.5 6a2.25 2.25 0 012.25-2.25H18A2.25 2.25 0 0120.25 6v2.25A2.25 2.25 0 0118 10.5h-2.25a2.25 2.25 0 01-2.25-2.25V6zM13.5 15.75a2.25 2.25 0 012.25-2.25H18a2.25 2.25 0 012.25 2.25V18A2.25 2.25 0 0118 20.25h-2.25A2.25 2.25 0 0113.5 18v-2.25z" />
+        </svg>
+        <span class="font-mono">{{ concurrencyUsed }}</span>
+        <span class="text-gray-400 dark:text-gray-500">/</span>
+        <span class="font-mono">{{ concurrencyMax }}</span>
+      </span>
+    </div>
+
+    <!-- 会话数 -->
+    <div v-if="sessionsMax > 0" class="flex items-center gap-1">
+      <span
+        :class="[
+          'inline-flex items-center gap-1 rounded-md px-1.5 py-0.5 text-[10px] font-medium',
+          capacityClass(sessionsUsed, sessionsMax)
+        ]"
+      >
+        <svg class="h-2.5 w-2.5" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+          <path stroke-linecap="round" stroke-linejoin="round" d="M15 19.128a9.38 9.38 0 002.625.372 9.337 9.337 0 004.121-.952 4.125 4.125 0 00-7.533-2.493M15 19.128v-.003c0-1.113-.285-2.16-.786-3.07M15 19.128v.106A12.318 12.318 0 018.624 21c-2.331 0-4.512-.645-6.374-1.766l-.001-.109a6.375 6.375 0 0111.964-3.07M12 6.375a3.375 3.375 0 11-6.75 0 3.375 3.375 0 016.75 0zm8.25 2.25a2.625 2.625 0 11-5.25 0 2.625 2.625 0 015.25 0z" />
+        </svg>
+        <span class="font-mono">{{ sessionsUsed }}</span>
+        <span class="text-gray-400 dark:text-gray-500">/</span>
+        <span class="font-mono">{{ sessionsMax }}</span>
+      </span>
+    </div>
+
+    <!-- RPM -->
+    <div v-if="rpmMax > 0" class="flex items-center gap-1">
+      <span
+        :class="[
+          'inline-flex items-center gap-1 rounded-md px-1.5 py-0.5 text-[10px] font-medium',
+          capacityClass(rpmUsed, rpmMax)
+        ]"
+      >
+        <svg class="h-2.5 w-2.5" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+          <path stroke-linecap="round" stroke-linejoin="round" d="M12 6v6h4.5m4.5 0a9 9 0 1 1-18 0 9 9 0 0 1 18 0Z" />
+        </svg>
+        <span class="font-mono">{{ rpmUsed }}</span>
+        <span class="text-gray-400 dark:text-gray-500">/</span>
+        <span class="font-mono">{{ rpmMax }}</span>
+      </span>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+interface Props {
+  concurrencyUsed: number
+  concurrencyMax: number
+  sessionsUsed: number
+  sessionsMax: number
+  rpmUsed: number
+  rpmMax: number
+}
+
+withDefaults(defineProps<Props>(), {
+  concurrencyUsed: 0,
+  concurrencyMax: 0,
+  sessionsUsed: 0,
+  sessionsMax: 0,
+  rpmUsed: 0,
+  rpmMax: 0
+})
+
+function capacityClass(used: number, max: number): string {
+  if (max > 0 && used >= max) {
+    return 'bg-red-100 text-red-700 dark:bg-red-900/30 dark:text-red-400'
+  }
+  if (used > 0) {
+    return 'bg-yellow-100 text-yellow-700 dark:bg-yellow-900/30 dark:text-yellow-400'
+  }
+  return 'bg-gray-100 text-gray-600 dark:bg-gray-800 dark:text-gray-400'
+}
+</script>