feat(plugins): 悬浮状态胶囊（B3 落地，复刻 ZCode 药丸⇄面板二态）

apps/desktop/src/main/plugins/plugin-host.ts

@@ -132,6 +132,8 @@ class PluginHost {
   /** 状态胶囊/工具栏按钮：pluginId → (itemId → data) */
   private statusItems = new Map<string, Map<string, StatusItem>>()
   private toolbarButtons = new Map<string, Map<string, ToolbarButtonDef>>()
+  /** 状态条目最近写入时间（悬浮胶囊"最新消息"判定），key = pluginId\0itemId */
+  private statusUpdatedAt = new Map<string, number>()
   /** 跨插件服务注册表（pluginId → serviceName → impl）；每次 runtime 重建时清空重建 */
   private services = new Map<string, Map<string, unknown>>()
   /** 已声明的存储 schema（api.storage.declareSchema；管理页 Tooltip 与 Agent 内省数据源） */
@@ -339,6 +341,7 @@ class PluginHost {
     log.info('reload begin')
     this.statusItems.clear()
     this.toolbarButtons.clear()
+    this.statusUpdatedAt.clear()
     this.services.clear()
     this.storageSchemas.clear()
     await this.scan()
@@ -534,7 +537,14 @@ class PluginHost {
   uiState(): PluginsUiState {
     const status: PluginStatusEntry[] = []
     for (const [pluginId, items] of this.statusItems) {
-      for (const [itemId, item] of items) status.push({ pluginId, itemId, item })
+      for (const [itemId, item] of items) {
+        status.push({
+          pluginId,
+          itemId,
+          item,
+          updatedAt: this.statusUpdatedAt.get(`${pluginId}\0${itemId}`) ?? Date.now()
+        })
+      }
     }
     const toolbar: PluginToolbarEntry[] = []
     for (const [pluginId, buttons] of this.toolbarButtons) {
@@ -552,8 +562,14 @@ class PluginHost {
       items = new Map()
       this.statusItems.set(pluginId, items)
     }
-    if (item) items.set(itemId, item)
-    else items.delete(itemId)
+    const stampKey = `${pluginId}\0${itemId}`
+    if (item) {
+      items.set(itemId, item)
+      this.statusUpdatedAt.set(stampKey, Date.now())
+    } else {
+      items.delete(itemId)
+      this.statusUpdatedAt.delete(stampKey)
+    }
     if (items.size === 0) this.statusItems.delete(pluginId)
     this.send('plugins:uiState', this.uiState())
   }
@@ -581,6 +597,9 @@ class PluginHost {
   private clearPluginUi(pluginId: string): void {
     this.statusItems.delete(pluginId)
     this.toolbarButtons.delete(pluginId)
+    for (const key of [...this.statusUpdatedAt.keys()]) {
+      if (key.startsWith(`${pluginId}\0`)) this.statusUpdatedAt.delete(key)
+    }
     this.settingsSchemas.delete(pluginId)
     this.dropSettingsCallbacks(pluginId)
     this.services.delete(pluginId)