fix(website): resolve extension owner plugin

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 31016278-f98b-48ef-8a77-430091b34b91

eng/extension-plugin-ownership.test.mjs

@@ -0,0 +1,61 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import {
+  buildExtensionPluginOwners,
+  resolveExtensionPluginName,
+} from "./extension-plugin-ownership.mjs";
+
+const namespace = "com.github.awesome-copilot";
+
+test("resolves an extension bundled only by its parent plugin", () => {
+  const owners = buildExtensionPluginOwners([
+    {
+      directoryName: "ember",
+      manifest: {
+        name: "ember",
+        extensions: {
+          [namespace]: {
+            extensions: ["./extensions/daily-focus-board"],
+          },
+        },
+      },
+    },
+  ]);
+
+  assert.equal(
+    resolveExtensionPluginName("daily-focus-board", owners),
+    "ember"
+  );
+});
+
+test("prefers a same-named standalone plugin over another owner", () => {
+  const owners = buildExtensionPluginOwners([
+    {
+      directoryName: "parent-plugin",
+      manifest: {
+        name: "parent-plugin",
+        extensions: {
+          [namespace]: {
+            extensions: ["./extensions/daily-focus-board/"],
+          },
+        },
+      },
+    },
+    {
+      directoryName: "daily-focus-board",
+      manifest: { name: "daily-focus-board" },
+    },
+  ]);
+
+  assert.equal(
+    resolveExtensionPluginName("daily-focus-board", owners),
+    "daily-focus-board"
+  );
+});
+
+test("preserves the extension name when no plugin owns it", () => {
+  assert.equal(
+    resolveExtensionPluginName("daily-focus-board", new Map()),
+    "daily-focus-board"
+  );
+});