fix: replace code-preview.vue with TypeScript render function to fix SSR ERR_UNKNOWN_FILE_EXTENSION

[NullVoxPopuli-ai-agent]

Problem

Fixes #39

When a project uses vite-plugin-ember and runs vitepress build, it fails with:

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".vue" for .../vite-plugin-ember/src/vitepress/code-preview.vue

Root cause: dist/vitepress/setup.js contains a dynamic import pointing back to the raw .vue source:

// dist/vitepress/setup.js (compiled from setup.ts line 79)
const CodePreview = defineAsyncComponent(
  () => import('../../src/vitepress/code-preview.vue'),
);

During VitePress's SSR build, vite-plugin-ember is loaded from node_modules and treated as external — its dynamic imports are resolved by Node.js native ESM, not Vite's transform pipeline. Node.js ESM does not recognise .vue as a valid module extension, so it throws ERR_UNKNOWN_FILE_EXTENSION.

Fix

Convert code-preview.vue to code-preview.ts using Vue's defineComponent + render-function API:

• tsc compiles it to dist/vitepress/code-preview.js — a plain JS file that Node.js ESM can load natively.
• setup.ts now imports ./code-preview.js (the compiled output) instead of ../../src/vitepress/code-preview.vue.
• Scoped CSS is replaced with a lightweight runtime style-injection that runs once on first client mount (guarded by document check, so SSR-safe).
• The ./components/CodePreview package export is updated to point to the compiled dist/vitepress/code-preview.js.

Test plan

• cd vite-plugin-ember && pnpm build compiles without errors
• dist/vitepress/code-preview.js exists and imports only .js/built modules
• dist/vitepress/setup.js imports ./code-preview.js, not a .vue file
• VitePress docs build (cd docs && pnpm build) completes without the extension error
• Live demo components still render correctly in the browser

🤖 Generated with Claude Code