fix: 切换工作台后数据不刷新

- 根因: ensureStandardProposals每次触发return跳过ensureTabData
- 修复: ensureTabData移到ensureStandardProposals之前
- 增加_proposalsInitialized一次性flag避免重复检查
- switchTenant改为async+await load()
- 版本号 v1.2.0.6

templates/index.html

@@ -76,7 +76,7 @@
     <header class="topbar border-b border-slate-200 bg-white px-8 py-5">
       <div class="flex items-center gap-3 w-full">
         <div class="flex-1">
-          <p class="eyebrow text-xs font-semibold uppercase tracking-[0.18em] text-blue-700">OPC Manager <span class="ml-2 text-xs font-normal text-slate-400 tracking-normal">v1.2.0.5</span></p>
+          <p class="eyebrow text-xs font-semibold uppercase tracking-[0.18em] text-blue-700">OPC Manager <span class="ml-2 text-xs font-normal text-slate-400 tracking-normal">v1.2.0.6</span></p>
           <div class="flex items-center gap-4 mt-1">
             <h1 class="text-2xl font-semibold" id="workspaceTitle">科普 OPC 工作台</h1>
             <div class="hidden sm:flex items-center gap-1.5 bg-gradient-to-r from-blue-50 to-indigo-50 border border-blue-100 rounded-full px-4 py-1.5">