refactor: replace MJPEG streaming with screenshot + meta-refresh

- Remove multipart/x-mixed-replace streaming (broken on Chromium)
- Add per-view screenshot rendering with base64 HTML embedding
- Implement resource inlining for CSS, images, and favicons
- Add render locks to prevent overlapping Puppeteer operations
- Simplify UpdateViewBody type to extend Partial<CreateViewBody>
- Update browser args for better stability
- Standardize formatting (tabs to spaces)

package.json

@@ -12,4 +12,4 @@
   "devDependencies": {
     "@types/bun": "^1.3.13"
   }
-}
+}