Renderer: vendor live-bridge scripts; GPU backend unblocked (60fps)

- emulator/render-bridge/: the pod->Dave's-renderer live bridge (rescued
  from session scratchpad): live_bridge.py (first-person cam from the 0x1f
  pose, arrow-key eye-height trim), fp/chase offline renders, fifobridge,
  diagnostics, gauge_arena[_sound].conf, and launch_pod.ps1 (one-command
  pod+bridge restart: pentapus VPX_EXPLODE + AWE32 sound + GL bridge).
- _backend.py: renderer selection -- vrview_gl.GLRenderer (moderngl) by
  default, VRVIEW_SOFT=1 for the software reference; backend-agnostic
  frame save via last_frame.
- GPU backend runs on side-by-side CPython 3.13 (moderngl/glcontext cp313
  wheels; no MSVC needed): 63fps headless / 60.7 windowed vs 21fps software
  on the same scene, and the GL path also draws the vertex-alpha cloud dome.
- vrview.py: VRVIEW_GAMMA env selects DAC gamma (1.25 live-renderer legacy
  vs 1.7 per the original GAMMA.C) for A/B against the real pod.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

emulator/render-bridge/diag.py

@@ -0,0 +1,15 @@
+import os,sys
+sys.path.insert(0, r"C:\VWE\TeslaRel410\dpl3-revive\patha")
+os.environ.setdefault("SDL_VIDEODRIVER","dummy")
+from vrboard import VirtualBoard, Assembler
+from decode_anim import find_framed_start
+data=open("bt8.raw.bin","rb").read()
+b=VirtualBoard(); a=Assembler(); a.feed(data[find_framed_start(data):])
+for m in a:
+    try: b.handle(m)
+    except Exception: pass
+    if b.frames>=600: break
+print("frames",b.frames,"munga",getattr(b,"munga",None))
+for attr in ("anim","anim_abs"):
+    v=getattr(b,attr,None)
+    print(attr, type(v).__name__, (len(v) if v is not None else None), (list(v)[:6] if v else None))