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  superseded BEAR_*.tres, marketing/spare PNGs, a spare font weight and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

Blender/create_matador_anims.py

@@ -1,6 +1,6 @@
 """
-Blender 5.1 script: create walk + idle animations for matador_v02.
-Run:  blender --background matador_v02.blend --python create_matador_anims.py
+Blender 5.1 script: create walk + idle animations for matador_v03.
+Run:  blender --background matador_v03.blend --python create_matador_anims.py
 """
 import bpy, math, os
 
@@ -130,7 +130,7 @@ ti.name = 'idle'
 si = ti.strips.new('idle', 0, idle)
 
 # ── export FBX ─────────────────────────────────────────────────────────────────
-fbx_path = os.path.join(os.path.dirname(bpy.data.filepath), 'matador_v02.fbx')
+fbx_path = os.path.join(os.path.dirname(bpy.data.filepath), 'matador_v03.fbx')
 bpy.ops.export_scene.fbx(
     filepath=fbx_path,
     use_selection=False,