test: Add a test harness for the built card (#2653)

Mounts the card from `dist/` the way Home Assistant does, by URL with a
HACS tag, and asserts the entry stays a facade, that no chunk imports
it, that the browser is served the file unmodified, and that the card
starts up and fetches a language chunk lazily.

Runs in Chromium, Firefox and WebKit, so a change of bundler or minifier
is checked against every engine.

tests/card-controller/card-element-manager.browser.test.ts

@@ -1,7 +1,7 @@
 import { describe, expect, it, onTestFinished } from 'vitest';
 
 import { createLogAction } from '../../src/utils/action';
-import { MountedCard } from '../browser/mounted-card';
+import { MountedCardFactory, type MountedCard } from '../browser/mounted-card';
 import {
   CARD_INITIALIZED_MESSAGE,
   createInitializedAutomation,
@@ -18,7 +18,7 @@ import {
 const KEY_MESSAGE = /key pressed/;
 
 const mountCard = async (): Promise<MountedCard> => {
-  const card = await MountedCard.create(
+  const card = await MountedCardFactory.createFromSource(
     createStillImageCardConfig({
       automations: [
         createInitializedAutomation(),