Fix map thumbnails for new BOOTSTRAP_CONFIG, add @license (v1.1.2)
The game moved its asset manifest/CDN base out of the top-level
window.ASSET_MANIFEST / window.CDN_BASE globals into
window.BOOTSTRAP_CONFIG.{assetManifest,cdnBase}, which broke map
thumbnail (and unit-icon) resolution in the settings popup. assets.ts
now reads the legacy globals first and falls back to BOOTSTRAP_CONFIG
(|| chaining, so a defined-but-empty legacy global still falls through).
Also add the missing @license (AGPL-3.0-or-later) to the userscript
metadata header, and cover the BOOTSTRAP_CONFIG path in the smoke test.
