fix(admin): LLM 路由显示不准确

- 默认路由改为动态取第一个活跃提供商（当前为 nvidia step-3.7-flash）
- 合规审查标签改为固定 sensenova (deepseek-v4-flash)
- 移除硬编码的 opencode-go 标签

platform/frontend/admin.html

@@ -108,10 +108,10 @@
                     <div v-if="activeTab === 'llmconfigs'">
                         <div style="margin-bottom:12px;padding:10px 16px;background:#f0f9eb;border-radius:6px;border:1px solid #e1f3d8;font-size:13px;display:flex;align-items:center;gap:8px;flex-wrap:wrap">
                             <span>🤖 LLM 路由：</span>
-                            <el-tag type="success" size="small" effect="dark" v-for="c in llmConfigs.filter(x=>x.is_active)" :key="c.id">{{ c.provider }} ({{ c.model }})</el-tag>
-                            <span style="color:#999">← 默认（趋势/采集/创作）</span>
+                            <el-tag type="success" size="small" effect="dark">{{ defaultProvider }} ({{ defaultModel }})</el-tag>
+                            <span style="color:#999">← 默认（趋势/采集/创作/优化）</span>
                             <span style="margin:0 4px;color:#ccc">|</span>
-                            <el-tag type="warning" size="small" effect="dark">opencode-go (deepseek-v4-flash)</el-tag>
+                            <el-tag type="warning" size="small" effect="dark">sensenova (deepseek-v4-flash)</el-tag>
                             <span style="color:#999">← 合规审查固定</span>
                         </div>
                         <div class="toolbar">
@@ -1100,7 +1100,16 @@ const llmConfigs = ref([]);
                     else { switchTab('users'); }
                 });
 
+                const defaultProvider = computed(() => {
+                    const active = llmConfigs.value.filter(x => x.is_active);
+                    return active.length ? active[0].provider : '-';
+                });
+                const defaultModel = computed(() => {
+                    const active = llmConfigs.value.filter(x => x.is_active);
+                    return active.length ? active[0].model : '-';
+                });
                 return {
+                    defaultProvider, defaultModel,
                     activeTab, switchTab,
                     llmConfigs, llmConfigsLoading, llmConfigDialogVisible, llmConfigForm, llmConfigDialogTitle, showLLMConfigDialog, saveLLMConfig, deleteLLMConfig,
                     platformConfigs, platformConfigsLoading, platformConfigsRequested, pcShowActiveOnly, showPcDialog, pcForm, pcDialogTitle, showPcDialogFn, savePcForm, editingPcPlatform,