PHLEGM v8 Checkpoint 71 - Uniform CHOP Icon Framing

Problem: The shared physical VIEW-MM scale made small physical models appear
much smaller than other icons. Scaling each model independently per yaw frame
would cause visible pulsation and frame-to-frame recentering.

Correction:
- Per-model 3D bounding-box centering is computed from the baked triangle mesh.
- All vertices are projected through the entire 16-frame yaw sequence at the
  model's true physical SIZE-MM; full-sequence bounds establish the fit.
- ONE isotropic scale is selected per icon, fitted to ICON-FIT width and height.
- Every cached frame uses the same center and multiplier. No runtime hot-path
  reconstruction, re-projection or per-frame zoom.
- Real-world physical dimensions remain untouched in CHOP mesh/blueprint data.
- Black wireframe, hidden-surface elimination, metallic shading, label decals,
  PCB contacts, and Windows/Linux GUI display paths are preserved.

Blueprint directive: ICON-FIT|56|40|UNIFORM|ALL-YAW
Canvas: 64x48 pixels; 4px horizontal/vertical target margins.

Native regression: tools/native-tests/chop-icon-uniform-fit-smoke.bas
This checkpoint needs native FreeBASIC compilation and GUI smoke testing.
