character: idle standing pose and warm skin, not the grey mannequin

- mpfb_character_export.py: new --pose idle folds the A/T-bind arms down to
  a relaxed standing rest pose (baked via pose.armature_apply before export);
  new make_diffuse synthesizes a warm skin-tone diffuse with a darker
  shorts-suggestive band, replacing the Cycles v2-skin bake that came out
  black and was slow at 1024^2.
- write_png now encodes from img.pixels via numpy (fast) because img.save()
  writes black for an in-memory image.
- Re-exported idle character, re-imported to /Game/Test/Character (138 bones,
  warm M_Character_Export/T_Character_Diffuse); removed stale T_Skin_Diffuse.
- Untracked the review PNGs again: the Screenshots/ gitignore rule had been
  dropped and the parallel session had committed the PNGs, against the
  AGENTS.md 'never commit the PNGs' rule. Restored the ignore rule; only
  Screenshots/README.md stays tracked.
- README/roadmap/memory updated; review-01-character re-pended for approval.

ROADMAP.md

@@ -79,9 +79,12 @@ Owner: this session. Scope: the review scene used for all visual approval — th
 - [x] Extend the review floor beyond the hero façade: 160 m square centred on the façade, so façade shots stand on ground instead of the horizon band.
 - [x] Delete retired shots: the old `first-person` frame is gone and the camera list is now a single table so a change cannot leave an orphan.
 
-### Character development - open
+### Character development - active - 01a1b26b-3c94-707f-9665-2f6b4a79b564
 
-Follow-on work on the player avatar, after the review scene passes. None of it is `0.1.0` scope unless a release check requires it.
+Follow-on work on the player avatar, after the review scene passes. None of it is `0.1.0` scope unless a release check requires it. Taking the standing idle pose and the second skin/clothing-layer items here; the player-identity decision and the demo-map capsule belong to the coordinator / gameplay owner.
+
+- [x] Standing idle pose: `Tools/mpfb_character_export.py --pose idle` folds the A/T-bind arms down to a relaxed standing rest pose (baked via `pose.armature_apply` before export). Verified: `upperarm01.L` rest z −0.71 → −1.91 rad; re-exported, re-imported (138 bones) and rendered in `review-01-character`.
+- [x] Second skin tone / clothing layer: the v2-skin bake came out **black** (sampled RGB 0,0,0) and is slow at 1024²; we now synthesize a warm skin-tone diffuse directly (`Tools/mpfb_character_export.py` `make_diffuse`, with a darker shorts-suggestive bottom band) written to disk via a stdlib/numpy PNG encoder, because `img.save()` writes black for an in-memory image. Character now reads warm, not grey. Screenshot review pending (`Screenshots/review-01-character` re-pended).
 
 - [ ] Decide what the `0.1.0` player is: first-person-only, or a body that is visible in third person. The `0.2.0` milestone adds the MPFB body and camera toggle; `0.1.0` currently ships a capsule with a camera and no visible body.
 - [ ] Give the MPFB character asset a standing idle pose so review and gameplay shots show a person, not an A-pose bind (`/Game/Test/Character/character`).