Renders BT's 128x32 plasma display into a desktop window instead of
streaming to serial hardware. L4PLASMASCREEN.* copied verbatim from
RP412; the L4GREND.cpp selector diff applied (BT's only divergence
there is a comment -- no collision).
Verified: a 'Plasma Display' window opens and the game ticks normally
beside it (L4GAUGE=640x480x16 L4PLASMA=SCREEN).
Phase 3b (single-window MFD-split cockpit) is DEFERRED -- blocked on
the missing BT cockpit-layout geometry and BT's unfinished upstream MFD
dev-composite; the L4VB16 hand-merge is HIGH-risk (BT's dev-gauge
docking overlaps RP412's split rewrite). See context/steamification.md
and docs/BT412-ROADMAP.md. (Phase 3 of the roadmap)
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
