refactor: organise assets, tidy player.gd, unbreak fresh import

Assets grouped by role, within the constraint that FBX materials resolve
their textures by path relative to the FBX itself (verified by forcing a
reimport and reading back the albedo paths):

  assets/level/   scene.fbx + Level1_v1.fbx + the platform maps they look
                  up as siblings
  assets/logos/   the three attribution logos
  assets/         chara_red.fbx, background.fbx — these reach up into
                  ../sourceimages and so cannot move
  sourcefiles/    scene.blend, behind a .gdignore

The .blend move is a bug fix, not tidying. Godot hands every importable
.blend to a headless Blender, and that call never returns on this project
— a fresh clone stalls on first import, and the machine still had orphaned
Blender processes from an earlier attempt. Nothing loads the .blend: the
level geometry is baked into level_1.tscn.

player.gd: spell out ct/bt/d/ix/a, type the physics step, group the
members, and point the blue skin at sourceimages/low_blue_mat_* — the same
files assets/Chara_blue/ was a byte-identical copy of.

Co-Authored-By: Claude Opus 5 <[email protected]>

.gitignore

@@ -24,5 +24,11 @@ Exports/
 .idea/
 .DS_Store
 
+# DCC scratch output. Maya writes .tx render caches and swatch thumbnails next
+# to the textures it exports; Godot cannot read either of them.
+*.tx
+.mayaSwatches/
+*.blend1
+
 # Plugin specific
 addons/script-ide/*