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/背中/part.yaml

@@ -0,0 +1,175 @@
+id: 背中
+original_key: 背中
+resource: 肢中
+morph_x: 1
+morph_y: 3
+variants:
+- x: 0
+  y: 0
+  file: x0y0.svg
+- x: 0
+  y: 1
+  file: x0y1.svg
+- x: 0
+  y: 2
+  file: x0y2.svg
+fields:
+- name: 羽毛1
+- name: 羽毛2
+joints:
+- position: [
+  0.02365804436862975,
+  0.009226817482352786
+]
+- position: [
+  0.08020662908846857,
+  0.164914315192153
+]
+- position: [
+  0.07255127072461791,
+  0.11201394207007394
+]
+- position: [
+  0.071545291706398,
+  0.21721024809702624
+]
+- position: [
+  0.06282689669009595,
+  0.11650671893913629
+]
+- position: [
+  0.05420814222672252,
+  0.12326942213283076
+]
+- position: [
+  0.04700290105009538,
+  0.13306172795532215
+]
+- position: [
+  0.04202686084058744,
+  0.14477507348330923
+]
+- position: [
+  0.039389559529548215,
+  0.1581516119984586
+]
+- position: [
+  0.03938955952954823,
+  0.1716770183858475
+]
+- position: [
+  0.04202686084058744,
+  0.18505355690099687
+]
+- position: [
+  0.0470029010500954,
+  0.196766902428984
+]
+- position: [
+  0.054208142226722544,
+  0.20655920825147525
+]
+- position: [
+  0.06282689669009596,
+  0.2133219114451697
+]
+- position: [
+  0.07532582900397887,
+  0.21930787405234473
+]
+- position: [
+  0.07963856428626281,
+  0.13550000000000004
+]
+- position: [
+  0.058455127975897574,
+  0.16863095258788496
+]
+- position: [
+  0.03632713032394423,
+  0.035980704537156
+]
+- position: [
+  0.03258823575863232,
+  0.03796011930702701
+]
+- position: [
+  0.020085750089291803,
+  0.03684656683927145
+]
+- position: [
+  0.07907049948405709,
+  0.164914315192153
+]
+- position: [
+  0.08672585784790776,
+  0.11201394207007394
+]
+- position: [
+  0.08773183686612762,
+  0.21721024809702624
+]
+- position: [
+  0.09645023188242963,
+  0.11650671893913629
+]
+- position: [
+  0.10506898634580308,
+  0.12326942213283076
+]
+- position: [
+  0.11227422752243021,
+  0.13306172795532215
+]
+- position: [
+  0.11725026773193814,
+  0.14477507348330923
+]
+- position: [
+  0.11988756904297737,
+  0.1581516119984586
+]
+- position: [
+  0.11988756904297737,
+  0.1716770183858475
+]
+- position: [
+  0.11725026773193814,
+  0.18505355690099687
+]
+- position: [
+  0.11227422752243021,
+  0.196766902428984
+]
+- position: [
+  0.10506898634580308,
+  0.20655920825147525
+]
+- position: [
+  0.09645023188242963,
+  0.2133219114451697
+]
+- position: [
+  0.08395129956854674,
+  0.21930787405234473
+]
+- position: [
+  0.09489836531813567,
+  0.16863095258788496
+]
+- position: [
+  0.03184603960146293,
+  0.035980704537156
+]
+- position: [
+  0.03558493416677477,
+  0.03796011930702701
+]
+- position: [
+  0.03721113642398388,
+  0.03684656683927145
+]
+- position: [
+  0.0076061099436181,
+  0.011409164915427206
+]