Remove the unreleased Electron desktop package

packages/apps-electron was never released, and electron 28, electron-builder
and their tooling (got, tar, app-builder-lib, builder-util-runtime) were most
of the dependency advisories left in this repo. Drop the package, its scripts,
the build:electron CI step, its i18n namespace and the deps only it used
(concurrently included).

The shipped web bundle changes by one string: "apps-electron" leaves the
i18n namespace list.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tsconfig.json

@@ -4,9 +4,7 @@
     "baseUrl": "./packages",
     "composite": false,
     /*
-     * We have a couple of issues that forces us to disable this -
-     *  1. apps-electron is still CJS
-     *  2. some of our packaged dependencies are problematic
+     * Disabled since some of our packaged dependencies are problematic
      *
      * (also disabled in tsconfig.build.json)
      */