Restructure: move Vite project into app/, deploy build output to repo root

The webserver serves the repo checkout directly as static files, so
index.html at the repo root must be the production build (pointing at
hashed /assets/*.js) rather than the dev template (/src/main.tsx),
which was being served with an unrecognized application/octet-stream
MIME type and blocked by the browser.

- Move src/, public/, scripts/, server/, package.json, vite.config.ts,
  tsconfig.json, .env(.example), and the dev index.html into app/.
- Add app/scripts/deploy.mjs: copies app/dist/* into the repo root
  after every `vite build`, cleaning up stale hashed filenames.
- Wire it into `npm run build` (app/package.json).
- Update run.sh to operate from app/, and .gitignore for the new layout.
- Commit the current build output (index.html, assets/, manifest,
  sw.js, workbox-*.js, favicon.svg, icons/, LICENSE) to the repo root.
- Update README with the new project layout and deployment model.

.gitignore

@@ -1,11 +1,11 @@
-node_modules
-dist
-dist-ssr
+app/node_modules
+app/dist
+app/dist-ssr
 *.local
-.env
-.env.*
-!.env.example
+app/.env
+app/.env.*
+!app/.env.example
 .DS_Store
 *.log
-.vite
+app/.vite
 *.tsbuildinfo