Dance library: bundled clips bind to any rigged model + repertoire + manual BPM

- models/dance_library.glb: skeleton-only GLB with the 13 Mixamo dances,
  loaded at startup and bound BY BONE NAME to whatever rigged GLB the
  user loads — new models dance immediately, no baking needed.
- Repertoire UI (Media tab): checkbox chips of the available clips, the
  director only picks the ticked ones (none = all); persisted.
- 'Aggiungi animazioni': extra .glb clips load directly; .fbx are
  converted on the fly by Blender via a new anim:convert IPC and the
  bundled scripts/fbx2animglb.py (asarUnpacked for packaged builds).
- Manual BPM with TAP tempo: 0 = follow the detected beat, otherwise a
  pure metronome drives the dance clock.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/fbx2animglb.py

@@ -0,0 +1,31 @@
+# Convert a Mixamo animation FBX into a skeleton-only GLB clip for the
+# DJ Visualizer dance library (bones only, no mesh — tiny files).
+#   blender -b -P fbx2animglb.py -- input.fbx output.glb
+import bpy, sys, os
+argv = sys.argv[sys.argv.index('--')+1:]
+SRC, OUT = argv[0], argv[1]
+bpy.ops.wm.read_factory_settings(use_empty=True)
+bpy.ops.import_scene.fbx(filepath=SRC)
+arm = None
+for o in list(bpy.data.objects):
+    if o.type == 'ARMATURE' and arm is None:
+        arm = o
+    elif o.type == 'MESH':
+        bpy.data.objects.remove(o, do_unlink=True)
+name = os.path.splitext(os.path.basename(SRC))[0].replace('_with_skin', '')
+act = arm.animation_data.action if arm and arm.animation_data else None
+if not act:
+    raise SystemExit('nessuna animazione nel file')
+act.name = name
+act.use_fake_user = True
+ad = arm.animation_data
+ad.action = None
+tr = ad.nla_tracks.new()
+tr.name = name
+tr.strips.new(name, int(act.frame_range[0]), act)
+try:
+    bpy.ops.export_scene.gltf(filepath=OUT, export_format='GLB',
+        export_animations=True, export_animation_mode='NLA_TRACKS')
+except TypeError:
+    bpy.ops.export_scene.gltf(filepath=OUT, export_format='GLB', export_animations=True)
+print('EXPORT_OK')