docs(skill): the surface table, rig anchors, and asserting the consequence

The skill is this project's own instructions, and three commits made it wrong:
it described a runtime that re-guessed what every surface was, a lab that only
tuned weapon holds, and a suite that could not see any of the last five defects.
It also still listed a seventh character that is not in skins.json.

Records what is new — the surface table and how it is decided, the layered
tuning files and why a fixed rotation on the weapon mount is the wrong answer,
the rig lab — and what the work taught:

  * assert the CONSEQUENCE. Asking a model which clip it is playing reads a
    variable it set on itself, and says "Idle" just as happily when nothing is
    ticking. Asking whether an anchor saved says nothing about whether the gun
    moved.
  * four of the last five real defects came from looking at a PNG. Every one of
    them passed every assertion.
  * the line-work rule now exists twice, at build time and as the runtime
    fallback, and they must be changed together or a model with a surface table
    starts rendering differently from one without.

Also records momo's broken idle and the stray Icosphere under known-unsolved,
with what is worth suspecting first in each case, since neither is fixed.

Co-Authored-By: Claude Opus 5 <[email protected]>

.claude/skills/character-pipeline/references/stylization.md

@@ -23,10 +23,17 @@ rim term lights it brightly exactly where it is supposed to read as ink.
 it flat and unshaded. "Untextured" alone is NOT the test — that made every
 flat-coloured model render as a black silhouette, because Quaternius' mannequin
 has two untextured materials (a yellow body, lilac joints) and both were hidden
-as though they were an outline shell. `_is_line_work()` asks three things
-instead: is it named `eyes*`, is it drawn front-face-culled (the classic
-inverted-hull setup), or is its albedo near-black. An ink shell is black; a
-flat-coloured character is any colour at all.
+as though they were an outline shell. The test asks three things instead: is it
+named `eyes*`, is it drawn front-face-culled (the classic inverted-hull setup),
+or is its albedo near-black. An ink shell is black; a flat-coloured character is
+any colour at all.
+
+That test now runs at BUILD time (`tools/surface_map.classify_linework`) and its
+answer lives in the sidecar. `SkinSurfaces.guess()` is the same rule kept as the
+runtime fallback, for a model with no surface table — and the cull-mode half of
+it is re-run at runtime even when the table exists, because glTF has no way to
+say "draw only the backfaces" and an inverted hull cannot survive the round trip
+as a cull mode. Blender genuinely cannot see it; Godot can.
 
 What it then does:
 
@@ -37,9 +44,29 @@ What it then does:
   with `HL` in the name, which is the glint in the pupil and really is white.
 
 If a newly imported character comes out with a white halo, a black silhouette,
-or black eyes that should have irises, `_is_line_work()` and the name-matching
-below it are where to look. The conventions vary by source and this is the one
-place they are read.
+or black eyes that should have irises, the line-work test and the name-matching
+below it are where to look — now in `tools/surface_map.py`, mirrored by
+`SkinSurfaces.guess()`. **Change both or neither**: a model with a surface table
+would start rendering differently from one without.
+
+## Per-class art direction
+
+Because each surface says what it is, each class takes its own numbers
+(`LevelMaterials.CHARACTER_LOOK`). `body` is deliberately identical to what every
+surface used to get, so the calibration this was all built on does not move. The
+others are departures, each for a reason:
+
+| Class | Outline | Band | Why |
+|---|---|---|---|
+| body | 5.0 mm | 0.16 | unchanged — the baseline |
+| cloth | 5.8 mm | 0.13 | a garment's silhouette is most of what separates a character from the background at range; folds need a defined terminator to read as fabric |
+| hair | 3.4 mm | 0.20 | **the one that matters.** A hair mesh is dozens of near-parallel strands millimetres apart; at the body's 5 mm each strand's hull swallows its neighbour and the head reads as one solid dark cap |
+| accessory | 6.8 mm | 0.10 | small, rigid, usually the most saturated thing on the character — meant to pop |
+
+This required moving the outline from `material_overlay` on the INSTANCE to
+`next_pass` on each surface's material. Miku's body, face and hair are three
+surfaces of one mesh, so an instance-wide overlay can only ever give all three
+the same weight.
 
 Taila's eyes still render as black cards rather than amber irises. Her eye
 surfaces are untextured, and the glTF import hands every untextured surface a