Consolidate raw art under art/ and prune unused assets

Group all raw art by role under art/ (characters, levels, weapons, fx,
anim, textures, ui, icons, fonts, hdri, materials), matching the earlier
code reorg. Files are snake_case; asset uids are preserved so uid:// refs
still resolve, and every res:// path reference is rewritten across scenes,
scripts and project.godot.

- Move the used assets out of Assets/ Animations/ fonts/ HUD/ HDRI/
  Materials/ into art/; remove those dirs.
- Materials snake_cased: barrel_metal, barrel_wood, bear_claw_fx, fire.
- Delete unreferenced assets: alternate models, empty stub scripts,
  superseded BEAR_*.tres, marketing/spare PNGs, a spare font weight and
  the orphan M_Barrel_wood.gdshader.
- Blender: drop .blend auto-backups and matador_v01/v02 (+ stale v02 fbx);
  keep matador_v03 and repoint create_matador_anims.py to it. .gitignore
  now blocks all Blender/*.blend[0-9] backups.
- GLB Extract-Textures siblings (art/levels/*.png) kept and tracked.
- Document the art/ layout in CLAUDE.md.

Headless suite green; menu and gameplay shell boot clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FBbGXbzg3SD6ZBSadPPF5H

tools/bake_crowd_sheet.gd

@@ -1,6 +1,6 @@
 extends SceneTree
 ## Bakes an animated-billboard sprite sheet from the existing clapping crowd figure
-## (Animations/mees_plaksutab.glb, clip "ArmatureAction") so a whole stand of
+## (art/anim/crowd_clap.glb, clip "ArmatureAction") so a whole stand of
 ## spectators can render as camera-facing quads in one draw call instead of 72 skinned
 ## skeletons. Renders FRAMES evenly-spaced poses from a front orthographic camera on a
 ## transparent background and packs them into a single-row atlas.
@@ -8,13 +8,13 @@ extends SceneTree
 ## Needs a display — script mode renders to a real window (headless is blank):
 ##   godot --script tools/bake_crowd_sheet.gd
 ##
-## Output: res://Assets/crowd_clap_sheet.png — FRAMES cells wide, TWO rows: the top row
+## Output: res://art/textures/crowd_clap_sheet.png — FRAMES cells wide, TWO rows: the top row
 ## is the front view, the bottom row is the back view. The crowd shader picks the row
 ## with FRONT_FACING so spectators show their backs when the camera is behind them.
 
-const SRC     := "res://Animations/mees_plaksutab.glb"
+const SRC     := "res://art/anim/crowd_clap.glb"
 const CLIP    := &"ArmatureAction"
-const OUT     := "res://Assets/crowd_clap_sheet.png"
+const OUT     := "res://art/textures/crowd_clap_sheet.png"
 const FRAMES  := 8
 const CELL_H  := 192      # sprite cell height in px; width derived from the figure aspect
 const PAD     := 1.12     # framing margin around the figure's bounds