Commit Alpine.js to the repo instead of unpacking it at build time (closes #163)

static/js/alpine.min.js is now committed: package/dist/cdn.min.js from
the @alpinejs/csp 3.14.9 npm package, byte for byte, taken once from the
package file that was in 3p/. The build no longer unpacks it, so
script/assets, the assets make target, its Dockerfile steps and the
ignore entries for the file are gone, and so is the package file.
Prettier and ESLint both ignore the file, so it stays as published.
Comments and the README now describe the committed file.

Model: opus-5-5

eslint.config.mjs

@@ -5,7 +5,7 @@
 // REPO_POLICIES.md states that a linter can check: const for everything,
 // let only for a variable that is reassigned, never var.
 export default [
-    // Alpine.js, extracted from 3p/ by make assets; not ours to lint.
+    // Alpine.js, committed as published; not ours to lint.
     { ignores: ["static/js/alpine.min.js"] },
     {
         // The pages load static/js/app.js as a classic script, not a module.