contribute.js ships but no page loads it (2 specs can never pass); 2D_Editor.html loads a three.js path deleted upstream (404 at CDN)

[chertsa]

Two cases at master (55900e2d, both still true at 5b48490) where shipped code references
something that is not there, so the feature silently cannot work:

1. contribute.js is in the tree, and no script tag anywhere loads it. Consequently
APP.contributeBuilding is always undefined, and the two specs that assert it
(20-s250-polish 20.22 / 20.23, "Import card has Share button" / "contributeBuilding uploads
with meta JSON") can never pass. Either a <script src="contribute.js"> was lost from
index.html, or the feature was retired and the specs remain.

2. 2D_Editor.html loads
https://cdn.jsdelivr.net/npm/three@0.160.0/examples/js/controls/OrbitControls.js — a path
three.js removed around r150. It is a 404 at the CDN today, so the editor stops at
"Initializing…" for everyone, everywhere. The maintained path is
examples/jsm/controls/OrbitControls.js (ES module), or pin a pre-r150 three for that page as
sandbox/loader.js already does with r128.

Happy to provide repro details for either — both were found by loading the pages headless and
counting failed requests.