Dependencies: drop unused and dead ones, close the remaining advisories

- yarn.lock refreshed within existing ranges for the open advisories.
- copy-webpack-plugin 11 -> 14 (serialize-javascript 7) and
  terser-webpack-plugin 5.6: build:www output is identical except four
  chunks where terser now emits `a ?? b` for `null == a ? b : a`.
- testcontainers (page-addresses, test-support) and devtron were never
  imported: removed (undici, @fastify/busboy, highlight.js went with
  them).
- The crypto-browserify webpack fallback was dead: build:www is
  byte-identical without it, so the fallback and the dependency are gone
  and a future `crypto` import fails the build instead of shipping a
  polyfill.
- braces resolves to @pezkuwi/braces 3.0.4, which limits nesting depth
  (CVE-2026-93687; no upstream release).

packages/apps/webpack.base.cjs

@@ -154,7 +154,6 @@ function createWebpack (context, mode = 'production') {
       extensions: ['.js', '.jsx', '.mjs', '.ts', '.tsx'],
       fallback: {
         assert: require.resolve('assert/'),
-        crypto: require.resolve('crypto-browserify'),
         fs: false,
         http: require.resolve('stream-http'),
         https: require.resolve('https-browserify'),