feat(clothing): tee, jeans and shoes as separate skinned meshes

Follows the character-artist clothing workflow literally: duplicate the body's own
faces for the garment base, solidify for cloth thickness, and keep each piece a
separate mesh. Attached as leader-pose components beside the hair, so no second rig.

- Tools/character_clothing_build.py builds three garments from the body mesh, trimmed
  geometrically (height band plus a width limit) instead of by dominant bone: the bone
  filter left holes wherever a face's strongest bone was outside the allowed list.
- Tools/ue_character_clothing_import.py imports them as CharacterTee / CharacterJeans /
  CharacterShoes, each arriving with its own single material slot.
- The pawn attaches all three, hidden with the body in first person.

Three traps recorded in MEMORY.md, each of which cost a build: MPFB weights its helper
geometry to groups that dominate every vertex, Blender refuses to apply a modifier to a
mesh with shape keys, and object-mode polygon selection is discarded on entering edit
mode - the delete wiped the whole garment.

Known defects, in TODO.md: the garments have coverage holes at shoulders, hips and
knees, and the hair reads light and wispy since its material was repointed to the
masked strand sheet.

TODO.md

@@ -22,7 +22,9 @@ Actionable task list for this project. This file is the single, central place fo
   - **The card layout now hugs the skull.** Each card is oriented by the scalp normal at its anchor — the length runs along the downward tangent, the width across it, and a small lift at the tip gives the cut volume. Three overlapping rows (7/9/10 cards, 26 total, 468 tris) replaced the single outward-pointing ring that read as a spiked crown. Overlap is what stops cards reading as separate spikes.
   - **Skin still needs work.** `M_Character_Skin` (constant tone 0.62/0.42/0.33, roughness 0.58) is built and the pawn calls `SetMaterial(0, ...)`, but the body still renders neutral grey in review shots, so the assignment is not taking. The baked `T_Character_Diffuse` cannot be used either: sampling it renders the body black, so the MPFB mesh's UVs do not map onto that bake. Next: verify the slot index after `SetSkeletalMesh`, or assign in `BeginPlay` instead of the constructor.
   - **Character blueprint and evaluation tools exist.** `Tools/comfyui_character_blueprint.py` generates a four-view sheet (front/side/back/head) from one description with fixed seeds; `Tools/character_match.py` compares a render against it and reports aspect, fill, coverage, mean CIE76 and palette distance plus a side-by-side montage. First result against `Screenshots/demo/review-demo-third-person-front.png`: **aspect delta 1.24, fill delta 0.12, mean ΔE 31.9, palette ΔE 25.4** — and the montage shows why: the model is a **nude body**, the blueprint is clothed (navy tee, jeans, sneakers).
-  - **Clothing is the largest visible gap** and is not in this patch's scope: the body carries no garments, so every colour and silhouette metric is dominated by the missing clothes rather than by skin or hair tuning.
+  - **Clothing exists now** (`Tools/character_clothing_build.py` + `Tools/ue_character_clothing_import.py`): tee, jeans and shoes as three separate skinned meshes, built from the body's own faces per the character-artist workflow (duplicate faces, solidify for thickness, one mesh per piece), imported as `CharacterTee` / `CharacterJeans` / `CharacterShoes` and attached as leader-pose components. The navy tee, dark jeans and off-white shoes read correctly at review distance.
+  - **The garments have coverage holes.** Grey skin shows through at the shoulders, hips and knees. Solidify offset (1 cm) is not enough where the body is convex, and trimming by x-width removes faces the body then shows through. Next: raise the offset, or grow the garment along its own normals after the solidify.
+  - **Hair reads light and wispy** since its material instance was repointed to `M_Character_Hair_Mat` (masked strand sheet): the alpha is cutting the cards into separate hairs and the base colour is being lifted by the texture. Either darken the texture or drive colour from a constant and use the sheet only as an opacity mask.
   - **Figure segmentation is explicit, not automatic.** Auto-detection failed on the review shots: the backdrop (sky band, pale wall, dark pavement) is larger and more saturated than the subject, so every size-based rule picked a backdrop blob. `--render-box` takes the figure box as fractions of the frame. A background plate rendered without the character would make this automatic.
   - `Tools/ue_character_materials.py` (wiring the generated textures into the skin and hair materials) **segfaults in the headless commandlet** when it edits the material graph. Not wired; the hair keeps the dark base colour it carries from Blender. Needs either an editor-session run or a material asset built from scratch instead of edited in place.