project.godot's API URLs already pointed at UAT (us3q.ranaze.com), but
deployment_environment itself was still "development" - a leftover
label that never matched the actual origin. Since the UAT-only feature
gates (Dynamic Questions, CCS Cases, Flashcards) check for the literal
"uat" value, running from the Godot editor/debugger hid all three even
though it's UAT in every other respect.
Set it to "uat" to match reality, and update the two places that
sed-patch this value at build time (web/Dockerfile for the UAT/PRD web
builds, tools/export_steam_release.sh for the Steam build) so they
still match the source string they're replacing.
Replaces the OS/window icon with the new dark-background logo design,
and derives a transparent shield-mark cutout (via chroma-key against
the flat background) for the in-app login/sidebar mark and the web
loading-screen logo. Brand.ranaze_mark_texture() no longer needs the
AtlasTexture crop since the new source asset is already tightly
cropped to the mark.
hz