PHLEGM v8 - Checkpoint 75: solid-white front faces / black feature-only edges

Canonical icon raster style:
- Visible, front-facing polygons are solid opaque #FFFFFFFF (white).
- Background and negative-space cutouts stay fully transparent.
- True #FF000000 black wire is an OVERLAY only on front-visible feature edges:
  exterior contours, cutout rims and edges between distinctly angled faces.
- Any near-coplanar edge (<= FEATURE-ANGLE, 5 degrees by default) is suppressed.
- No black seam on triangle diagonals, coplanar greedy-quad splits, or subdivided
  flat patches; no back/hidden geometry drawn over the front surfaces.
- Solid white replaces metallic diffuse/specular shading and material palette.
- Colored contacts and CHR decals intentionally not composited in white mode.

Implementation:
- Draw only front-facing triangles into white color and a depth/face-normal
  owner buffer. Raster owner stores visible signed normal, not triangle ID.
- Omit the previous indiscriminate quad-perimeter wire pass; it drew false
  boundaries between adjacent coplanar polygons.
- Overlay black using only silhouette/feature transitions from the final
  depth-tested, front-facing owner buffer.
- Define style via cfg/instructions/PHLEGM.chop.phlegm PRESENTATION and
  FEATURE-ANGLE|5|DEGREES. Compatible with the existing geometry pipeline.
- All prior 5%-of-largest-SIZE-MM physical thickness and framing preserved.

Tests: 9 models x 16 yaw frames x 2 hosts accept ONLY transparent/opaque
white/opaque black; coplanar seam synthetic fixture remains white and true
90-degree feature boundary becomes black, while a 3-degree seam is
suppressed and a 7-degree crease qualifies for an outline, without bleeding into transparent
background. Native compiler / GUI output still require target build testing.
