Initial commit: Phase 1+2 prototype

- Go backend with SQLite, JWT auth, file CRUD
- Vue 3 frontend with split/raw/WYSIWYG editor modes
- Markdown preview (marked, GFM)
- Formatting toolbar + keyboard shortcuts
- File tree with search, create, delete
- Light/dark theme toggle
- Admin panel (user management)
- Preferences (timezone, theme, default mode)
- Shared documents section (placeholder)
- Export: PDF, HTML, MD
- Build daemon (Python, stdlib only)
- Build job queue API
- Docker deployment

frontend/src/lib/markdown.js

@@ -0,0 +1,6 @@
+import { marked } from 'marked'
+
+export function renderMarkdown(md) {
+  if (!md) return ''
+  return marked(md, { gfm: true, breaks: true })
+}