Both are still in progress and shouldn't be reachable in production
(or local dev) yet - hide every entry point (nav sidebar, the
dashboard's "dynamic concepts due" review card, and the CCS Cases
mode card on the study selector) unless step3/deployment_environment
is "uat", the same setting that already drives the UAT badge. Added
Brand.is_uat_environment() as the shared check.
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.
icon_circle_box's perfectly-circular StyleBoxFlat (corner radius equal
to half the box size, no straight edges between corners) is a known
Godot degenerate case that draws a faint seam through the middle when
antialiasing is on and looks faceted at low corner_detail. Bumping
corner_detail and disabling antialiasing renders a clean circle at
these small badge/icon sizes instead - affects every icon_circle_box
call site (answer badges, stat tiles, avatars, etc.), not just the
question player.