feat(assets): wardrobe engine + proof t-shirt — batch-fit, offset-shell, 4-region tint, thrds logo (T-1089)

Engine: tooling/garment-fit/blender_batch_fit_skinned.py (G1 — the skinned
Surface-Deform batch the old script couldn't produce; self-check green),
blender_author_offset_shell.py (route c: garment shells from OUR body
segments, weights inherited by construction, bone-plane cuts, procedural
RGBA region mask, UV2 chest channel), make_logo.py. Shader:
toon_garment.gdshader — channel-blended 4-region tint + UV2 logo composited
after tint / before toon shading. Proof: tshirt_modern fitted to the six
healthy bodies, manifest entry with style:modern + logo_capable, thrds
wordmark, 18-assertion test suite, 216-capture chromakey QA.

Key finding (Q-060 evidence): single-reference SD-fit of an offset-shell
degrades on girth-divergent bodies (muscular_m worst) — 24mm standoff
tripled headroom but the mechanism limits. Route guidance recorded on
T-1089: per-body shell authoring for offset-shell garments; SD-fit for
derived/hand-authored ones.

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

client/assets/characters/clothing/tshirt_modern/coverage.json

@@ -0,0 +1,5 @@
+{
+  "hides": ["torso", "arm_upper_l", "arm_upper_r"],
+  "torso_variant": "full",
+  "multi_region": true
+}