Fix garbled Japanese/Unicode text in armature and mesh dropdowns

- Add proper caching to EnumProperty callbacks to prevent encoding corruption
- Use ASCII-safe identifiers (ARM_/MESH_ + pointer) with Unicode display names
- Add get_mesh_from_identifier() helper for safe mesh retrieval
- Update visemes panel to use new mesh identifier system
- Ensure stable string objects prevent Blender RNA encoding issues

functions/visemes.py

@@ -137,15 +137,17 @@ class AvatarToolkit_OT_PreviewVisemes(Operator):
             return False
             
         # Get mesh from UI selection
+        from ..core.common import get_mesh_from_identifier
         props = context.scene.avatar_toolkit
-        mesh_obj = bpy.data.objects.get(props.viseme_mesh)
+        mesh_obj = get_mesh_from_identifier(props.viseme_mesh)
         
         # Validate mesh
         return mesh_obj and mesh_obj.type == 'MESH'
     
     def execute(self, context: Context) -> Set[str]:
+        from ..core.common import get_mesh_from_identifier
         props = context.scene.avatar_toolkit
-        mesh = bpy.data.objects.get(props.viseme_mesh)
+        mesh = get_mesh_from_identifier(props.viseme_mesh)
         
         if props.viseme_preview_mode:
             VisemePreview.end_preview(mesh)
@@ -191,15 +193,17 @@ class AvatarToolkit_OT_CreateVisemes(Operator):
             return False
             
         # Get mesh from UI selection
+        from ..core.common import get_mesh_from_identifier
         props = context.scene.avatar_toolkit
-        mesh_obj = bpy.data.objects.get(props.viseme_mesh)
+        mesh_obj = get_mesh_from_identifier(props.viseme_mesh)
         
         # Validate mesh
         return mesh_obj and mesh_obj.type == 'MESH'
 
     def execute(self, context: Context) -> Set[str]:
+        from ..core.common import get_mesh_from_identifier
         props = context.scene.avatar_toolkit
-        mesh = bpy.data.objects.get(props.viseme_mesh)  # Changed from context.active_object
+        mesh = get_mesh_from_identifier(props.viseme_mesh)
         
         if not mesh or not mesh.data.shape_keys:
             self.report({'ERROR'}, t("Visemes.error.no_shapekeys"))