feat(macos): add Canvas A2UI renderer

vendor/a2ui/renderers/lit/src/0.8/ui/component-registry.ts

@@ -0,0 +1,58 @@
+/*
+ Copyright 2025 Google LLC
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      https://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+import { CustomElementConstructorOf } from "./ui.js";
+
+export class ComponentRegistry {
+  private registry: Map<string, CustomElementConstructorOf<HTMLElement>> =
+    new Map();
+
+  register(
+    typeName: string,
+    constructor: CustomElementConstructorOf<HTMLElement>,
+    tagName?: string
+  ) {
+    if (!/^[a-zA-Z0-9]+$/.test(typeName)) {
+      throw new Error(
+        `[Registry] Invalid typeName '${typeName}'. Must be alphanumeric.`
+      );
+    }
+
+    this.registry.set(typeName, constructor);
+    const actualTagName = tagName || `a2ui-custom-${typeName.toLowerCase()}`;
+
+    const existingName = customElements.getName(constructor);
+    if (existingName) {
+      // Constructor is already registered.
+      if (existingName !== actualTagName) {
+        throw new Error(
+          `Component ${typeName} is already registered as ${existingName}, but requested as ${actualTagName}.`
+        );
+      }
+      return;
+    }
+
+    if (!customElements.get(actualTagName)) {
+      customElements.define(actualTagName, constructor);
+    }
+  }
+
+  get(typeName: string): CustomElementConstructorOf<HTMLElement> | undefined {
+    return this.registry.get(typeName);
+  }
+}
+
+export const componentRegistry = new ComponentRegistry();