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>

build.rs

@@ -0,0 +1,14 @@
+//! Builds web/index.html and web/login.html from their TypeScript (web/build.mjs) into OUT_DIR,
+//! where src/web.rs include_str!s them. Needs node and `npm ci` run first.
+use std::process::Command;
+
+fn main() {
+    println!("cargo:rerun-if-changed=web");
+    println!("cargo:rerun-if-changed=package-lock.json");
+    let out = std::env::var("OUT_DIR").unwrap();
+    let status = Command::new("node")
+        .args(["web/build.mjs", &out])
+        .status()
+        .expect("building the web pages needs node on PATH (and `npm ci` run once)");
+    assert!(status.success(), "web/build.mjs failed; run `node web/build.mjs` to see why");
+}