Vite plugin — dev server HMR

Acceptance Criteria

• File watcher detects .md changes in dev mode
• Changed file is re-transformed through the full pipeline (parse → transform → render)
• Vite module graph is invalidated for the changed file via server.moduleGraph.invalidateModule()
• Browser receives update (full reload — same approach as existing sveltekit HMR)
• Level 2 warnings for cross-page runes display in terminal on file change
• No unnecessary re-transforms of unchanged files in Level 1 mode

Approach

1. Implement src/hmr.ts — hooks into Vite's configureServer and handleHotUpdate
2. On .md file change: invalidate module, send full reload
3. Reference packages/sveltekit/src/content-hmr.ts for existing pattern

Dependencies

• Create @refrakt-md/vite plugin — Level 1 static transform — core plugin must exist first

References

• Vite Plugin — Framework-Agnostic Rune Integration (Dev Server section)
• packages/sveltekit/src/content-hmr.ts — existing HMR implementation