revert: drop the alert feed widget, the notification center replaces it

src/ui/plugin-host/testing-host.tsx

@@ -71,7 +71,6 @@ import {
 } from "./shell-bridge";
 import { PluginViewPlaceholder } from "./PluginViewPlaceholder";
 import { resolveLayoutTabTarget } from "@/shell/shell-layout";
-import { getExtension, listExtensions } from "./extension-registry";
 import type { WorkspaceTabSnapshot } from "@/types/ui-types";
 
 function recordingShell(calls: ShellCall[]): TabShellCallbacks {
@@ -237,8 +236,6 @@ export async function renderPlugin(
         mine(hostEditorSectionList()).map((section) => section.id),
       dashboardCards: () =>
         mine(registeredDashboardCardList()).map((card) => card.id),
-      extensions: (pointId) =>
-        mine(listExtensions(pointId)).map((extension) => extension.id),
       settingsComponents: () =>
         listSettingsComponents()
           .filter((key) => key.startsWith(`${pluginId}:`))
@@ -321,16 +318,6 @@ export async function renderPlugin(
       );
     },
 
-    renderExtension(pointId, id, component = "view", props = {}) {
-      const extension = getExtension(pointId, id);
-      const Component =
-        extension?.pluginId === pluginId
-          ? extension.components?.[component]
-          : undefined;
-      if (!Component) missing(`an extension "${component}" component`, id);
-      return wrap(<Component {...props} />);
-    },
-
     renderDashboardCard(id) {
       const card = getRegisteredDashboardCard(id) ?? missing("a card", id);
       const Component = card.component;