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>

tsconfig.json

@@ -0,0 +1,12 @@
+{
+  // Type-checks web/src (npx tsc). Nothing is emitted: web/build.mjs does that with swc.
+  // The files are one script in one scope, not modules, which is why there are no imports.
+  "compilerOptions": {
+    "target": "es2022",
+    "lib": ["es2022", "dom", "dom.iterable"],
+    "noEmit": true,
+    "strict": false,
+    "skipLibCheck": true
+  },
+  "include": ["web/src/*.ts"]
+}