Replace marked.min.js with the marked npm package and update all references accordingly.

CLAUDE.md

@@ -18,7 +18,7 @@ Three-part Chrome extension:
 - **Runtime**: Chrome MV3 (Manifest V3)
 - **Language**: Vanilla JavaScript (ES6+), no frontend framework
 - **Styling**: Tailwind CSS v4 + PostCSS + Autoprefixer; CSS variables for theming; dark mode via `prefers-color-scheme`
-- **Markdown**: Custom HTML→Markdown converter in `content.js`; `marked.min.js` for preview rendering
+- **Markdown**: Custom HTML→Markdown converter in `content.js`; `marked` npm package for preview rendering
 - **Build**: Vite v8 with `vite-plugin-static-copy`
 
 ## Build & Development
@@ -66,7 +66,6 @@ src/
 ├── settings.html/.js/.css # Options page
 ├── content.js          # Page content extractor
 ├── background.js       # Service worker
-├── marked.min.js       # Bundled Markdown renderer
 └── icons/              # 16, 32, 48, 128px PNG icons
 dist/                   # Build output (gitignored)
 vite.config.js