The page's script is TypeScript in web/src, built and minified with swc

- web/src/*.ts: the script that was inline in index.html and login.html, split along its
  existing sections. Still one scope, concatenated in order, not modules.
- web/build.mjs strips the types, puts the script in the page and minifies it with swc;
  build.rs runs it into OUT_DIR and web.rs include_str!s the result. 137 KB -> 106 KB.
- npx tsc -p . type-checks web/src, loosely; the handful of annotations it needed
  change no behaviour.
- The Docker build installs node and swc (npm ci --omit=dev).
- Two list requests racing no longer let the older one win, and switching tabs clears
  the selection it closes, which made a browser test flaky.

Closes #23, #24.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/build.mjs

@@ -0,0 +1,52 @@
+// Builds the pages ipx serves: each page's TypeScript from web/src, types stripped and minified
+// by swc, put into the page in place of its <script data-src>, and the whole page minified.
+// build.rs runs it into OUT_DIR, where web.rs include_str!s the result, so the binary still
+// carries every page and nothing is served from disk.
+//
+//   node web/build.mjs [out-dir]      default out-dir: web/dist
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import swc from '@swc/core';
+import html from '@swc/html';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+
+// The files are one script, concatenated in this order, not modules: they share one top-level
+// scope, as the single inline script did, and code that runs at load needs what came before it.
+const PAGES = {
+  'index.html': ['util', 'feeds', 'feedpage', 'items', 'player', 'dialogs', 'events'],
+  'login.html': ['login'],
+};
+
+export function buildPage(name, { minify = true } = {}) {
+  const src = PAGES[name].map(f => fs.readFileSync(path.join(here, 'src', f + '.ts'), 'utf8')).join('\n');
+  const js = swc.transformSync(src, {
+    filename: name + '.ts',
+    jsc: {
+      parser: { syntax: 'typescript' },
+      target: 'es2022',
+      // Top-level names stay as they are: markup calls some of them by name (onclick="closeModal()")
+      // and the browser tests reach others (player, savePos) through page.evaluate.
+      minify: minify ? { compress: { toplevel: false }, mangle: { toplevel: false } } : undefined,
+    },
+    isModule: false,
+    minify,
+  }).code;
+  const page = fs.readFileSync(path.join(here, name), 'utf8');
+  const marker = /<script data-src="[^"]*"><\/script>/;
+  if (!marker.test(page)) throw new Error(`${name} has no <script data-src> to put its script in`);
+  // A function, so a `$&` or `$1` in the script is not read as a replacement pattern.
+  const out = page.replace(marker, () => `<script>${js}</script>`);
+  if (!minify) return out;
+  const r = html.minifySync(out, { minifyJs: false, minifyCss: true, removeComments: true });
+  const bad = (r.errors || []).filter(e => e.level === 'Error');
+  if (bad.length) throw new Error(`${name}: ${bad.map(e => e.message).join('; ')}`);
+  return r.code;
+}
+
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
+  const out = process.argv[2] || path.join(here, 'dist');
+  fs.mkdirSync(out, { recursive: true });
+  for (const name of Object.keys(PAGES)) fs.writeFileSync(path.join(out, name), buildPage(name));
+}