Fix PWA install: static manifest.json + proper SVG icon

- Replace blob: manifest (ignored by Chrome) with static manifest.json
- Replace data: URL icon with real icon.svg file
- Link manifest and apple-touch-icon directly in <head>
- Remove blob/data URL generation from app.js

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -1,5 +1,5 @@
 FROM nginx:alpine
-COPY index.html styles.css app.js sw.js /usr/share/nginx/html/
+COPY index.html styles.css app.js sw.js manifest.json icon.svg /usr/share/nginx/html/
 COPY nginx.conf /etc/nginx/conf.d/default.conf
 COPY docker-entrypoint.sh /docker-entrypoint.sh
 RUN chmod +x /docker-entrypoint.sh