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.

app/scripts/deploy.mjs

@@ -0,0 +1,48 @@
+// Copies the production build (app/dist) into the repository root, so the
+// webserver can serve the repo checkout directly as static files — no
+// server-side build step, no special MIME-type config, no reverse proxy
+// required. Run automatically as part of `npm run build`.
+//
+//   node scripts/deploy.mjs
+//
+import { readdir, rm, cp, unlink, copyFile } from "node:fs/promises";
+import { dirname, join, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const DIST = resolve(__dirname, "../dist");
+const REPO_ROOT = resolve(__dirname, "../../");
+
+const entries = await readdir(DIST, { withFileTypes: true });
+
+for (const entry of entries) {
+  const src = join(DIST, entry.name);
+  const dest = join(REPO_ROOT, entry.name);
+
+  if (entry.isDirectory()) {
+    // Directories (assets/, icons/) are pure build output — wipe and replace
+    // so stale, superseded hashed filenames don't pile up.
+    await rm(dest, { recursive: true, force: true });
+    await cp(src, dest, { recursive: true });
+    console.log(`  dir   ${entry.name}/`);
+    continue;
+  }
+
+  // Hashed, content-addressed files (e.g. workbox-<hash>.js) change name
+  // between builds — remove any previous versions before copying the new one.
+  const hashedPrefixMatch = entry.name.match(/^(workbox-)[0-9a-f]+(\.js)$/);
+  if (hashedPrefixMatch) {
+    const [, prefix, ext] = hashedPrefixMatch;
+    const siblings = await readdir(REPO_ROOT);
+    for (const sibling of siblings) {
+      if (sibling.startsWith(prefix) && sibling.endsWith(ext) && sibling !== entry.name) {
+        await unlink(join(REPO_ROOT, sibling));
+      }
+    }
+  }
+
+  await copyFile(src, dest);
+  console.log(`  file  ${entry.name}`);
+}
+
+console.log(`\nDeployed build output from ${DIST} -> ${REPO_ROOT}`);