Phase 0.3-0.5: SVG export + YAML sidecars + asset catalog

- Add hair class KeyMap entries (基髪→BaseHair, 前髪→FrontHair, 胸毛→ChestHair)
- Implement cardinal spline → cubic Bezier SVG export for all 175 body parts
- Generate YAML sidecar files (part.yaml) per part with metadata
- Write Catalog.yaml index for runtime asset loading
- Output to SlaveMatrix/Assets/Parts/{EnglishName}/ structure
- Each part directory contains part.yaml + x{x}y{y}.svg morph variants
- 838 SVGs across 324 morph variants, 175 sidecars, 1 catalog
- Extraction tool now serves as the asset build pipeline step

SlaveMatrix/Assets/Parts/目尻影左/part.yaml

@@ -0,0 +1,20 @@
+id: 目尻影左
+original_key: 目尻影左
+resource: 胴体
+morph_x: 1
+morph_y: 1
+variants:
+- x: 0
+  y: 0
+  file: x0y0.svg
+fields:
+- name: 目尻影
+joints:
+- position: [
+  0.005883410664338228,
+  0.0036910312264928323
+]
+- position: [
+  0.009449892066867003,
+  -0.002756905078307997
+]

SlaveMatrix/Assets/Parts/目尻影左/x0y0.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1 1">
+<g transform="translate(0.3257456317518053,0.1130072566562324) rotate(0) scale(1,1) translate(-0.009449892066867003,0.002756905078307997)"><path d="M 0.00842700664637154 0.003650403850211156 C 0.008248937489393714 0.003646787099523523 0.005866244098965404 0.003613774071339839 0.006290176762637623 0.0036070028419595596 C 0.005866244098965404 0.003613774071339839 0.0030939511756105254 0.0037420465828424208 0.0033398146823049174 0.0037316586027745084" fill="none" stroke="#000000" stroke-width="0.001"/>
+</g></svg>