fix(ui): address PR #99 review — character creation editor fixes

13 fixes from PR #99 review on #705 (character editor):

- #10/#11: Add _get_swatch_color() helper; fix stale closure in
  _make_color_swatch (reads current color at click time, not
  construction time); fix _on_modal_ok to use helper instead of
  wrong get_child(0) traversal
- #12: Replace HSV palette with D-165 hardcoded hex values (6×9
  rows, muted HSL per spec — reds/greens/blues/purples/browns/grays)
- #13: Fix fallback asset IDs to match actual files — hair: bald/
  bob/buzzed/long; heads: head_001–004; facial hair: beard/moustache/
  mutton_chops (stubble removed — no asset)
- #14: Remove invented "slot field" TODO comment; replace with
  name-prefix convention note
- #15: Fix overhead camera pitch 0.0°→-80.0° (0° was horizontal,
  not top-down as intended per D-158)
- #16: Make hair highlight swatch non-interactive (_make_display_swatch);
  remove _on_hair_highlight_changed and _hair_highlight_auto flag
- #17: Remove no-op self-assignment in _on_hair_selected; remove
  redundant assignment inside _hair_highlight_auto block
- #18: Store _clothing_dock_container/_accessory_dock_container as
  instance vars — eliminates fragile get_child(3).get_child(0) chain
- #19: Fix test_r_key_triggers_randomise — replaces assert_bool(true)
  with a real assertion checking body_type or skin_tone changed
- #20: Cache scan results in _cached_hair_ids/_cached_head_ids during
  tab build; _on_randomise() reads cache (no re-scan per keypress)
- #21: Fix character_visual.gd docstring "21 segments" → "18 segments"
- #22: Fix _get_accessory_ids_for_slot — apply slot name-prefix
  filtering instead of returning all accessories for every slot

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/scripts/rendering/character_visual.gd

@@ -6,7 +6,7 @@ extends Node3D
 ## pre-authored asset files. No runtime deformation — selects and attaches meshes.
 ##
 ## All asset paths derived programmatically from BASE_PATH + descriptor fields:
-##   bodies/{body_type}/seg_{name}.glb  (D-160: 21 segments per body type)
+##   bodies/{body_type}/seg_{name}.glb  (D-160: 18 segments per body type)
 ##   heads/templates/{head_id}.glb       (D-161: head as BoneAttachment3D)
 ##   hair/{hair_id}.glb                  (BoneAttachment3D to Head bone)
 ##   clothing/{item_id}/{body_type}.glb  (D-162: pre-fitted per body type)