style(ui): 表格配色收敛到全局墨色基调

- 统计卡：大数字统一墨色、标签统一次要灰，去掉绿/红/橙彩虹数字
- 所有语义色文字 300/200 浅色加深为 600/500（淡底深字，适配亮色主题）
- 徽章/胶囊 ring 与 border 统一为 500/25 细描边
- 滑动开关开态由绿改墨黑（对齐 vivid switch.on）
- .fp-* 徽章改为 vivid 同款淡底深字
- 跳过媒体覆盖层胶囊、暗色代码块等本就属于暗底的元素

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

frontend/src/views/ConcurrencyView.vue

@@ -84,12 +84,12 @@ onMounted(load)
             <td class="px-5 py-3.5 align-middle text-sm font-medium text-white/90">{{ g.name }}</td>
             <td class="px-3 py-3.5 align-middle text-right tabular-nums">
               <span v-if="g.max_concurrency > 0" class="text-white/85">{{ g.max_concurrency }}</span>
-              <span v-else class="text-emerald-300/90">不限制</span>
+              <span v-else class="text-emerald-600">不限制</span>
             </td>
             <td class="px-3 py-3.5 align-middle text-right tabular-nums text-white/70">{{ g.user_count }}</td>
             <td class="px-3 py-3.5 align-middle">
-              <span v-if="g.is_default" class="inline-flex items-center gap-1.5 rounded-full px-2.5 py-1 text-[11px] font-medium bg-rose-500/10 text-rose-300 ring-1 ring-rose-400/30">
-                <span class="w-1.5 h-1.5 rounded-full bg-rose-400"></span> 默认
+              <span v-if="g.is_default" class="inline-flex items-center gap-1.5 rounded-full px-2.5 py-1 text-[11px] font-medium bg-rose-500/10 text-rose-600 ring-1 ring-rose-500/25">
+                <span class="w-1.5 h-1.5 rounded-full bg-rose-500"></span> 默认
               </span>
               <button v-else @click="setDefault(g)" class="btn-soft text-xs">设为默认</button>
             </td>