[JeremyRH]

Refs #95

Problem

Playground renders its preview itself, outside Storybook's story-rendering pipeline, so no decorators apply to it.

What this changes

Makes the store key something the user chooses, so the two halves can be linked by name.

• makeLiveEditStory accepts an optional id, used as the store key instead of a generated one. Falls back to the previous generated id when omitted.
• Playground's existing id prop now keys that same store.

Passing the same id to both wires them together:

// Button.stories.tsx
export const Editable: Story = {};

makeLiveEditStory(Editable, {
  id: 'button-demo',
  code: buttonSource,
  availableImports: { 'my-library': MyLibrary },
});

{/* Button.mdx */}
<Playground id="button-demo" Container={({ editor }) => editor} />

<Story of={ButtonStories.Editable} />