Adds env-gated GE_D75 probe in title.c sub_GAME_7F007F30 (capped 8 lines).
Booted the bare front end through the gun-barrel sequence:
- Bond chr model + gun model entirely absent; both Model instances are
valid (non-NULL obj, numMatrices 21/1) -> 'model not loaded' ruled out.
- chrModelInstance->render_pos is valid and freshly written each frame
(== that frame's dynAllocate mtxlist base, clean double-buffer swap,
o2p returns it unchanged) -> the 'render_pos = stale dynAllocate arena'
hypothesis (D115 #5) is RULED OUT; do NOT land a persistent render_pos
buffer.
- Zero fast3d DL warnings during the sequence -> not the D144/D146
corrupt-sub-DL family.
Failure is downstream in drawjointlist/dotube vtx/node-DL resolution or an
off-screen basemtx. Next step: a drawjointlist-level probe. Full write-up
in PCPortResearch.md 'D75 Bug 2 - RUNTIME PROBE'.
-level_09 nonclear stable (91.66->91.62, D117 pan noise); build green.