feat: Add VRM Blender addon with complete import/export functionality

- Add core VRM addon infrastructure with manifest and registration
- Add common utilities module with file system, logging, and conversion helpers
- Add human bone mapper with support for multiple rigging standards (Mixamo, MMD, Unreal, Rigify, etc.)
- Add VRM 0.x and 1.x format support with property groups and handlers
- Add editor UI panels for VRM metadata, spring bones, and MToon materials
- Add exporter with glTF2 extension support for VRM format serialization
- Add importer with scene reconstruction and armature generation
- Add MToon shader support with auto-setup and material migration
- Add spring bone physics simulation with constraint handling
- Add node constraint editor for advanced rigging control
- Add comprehensive validation and error handling with user dialogs
- Add scene watcher for real-time property synchronization
- Add workspace management and preference system
- Include Python cache files and Blender manifest configuration
- This is the initial commit establishing the complete VRM addon ecosystem for Blender

common/progress.py

@@ -0,0 +1,87 @@
+# SPDX-License-Identifier: MIT OR GPL-3.0-or-later
+import math
+from collections.abc import Iterator
+from contextlib import contextmanager
+from typing import Final, Optional
+from uuid import uuid4
+
+import bpy
+from bpy.types import Context
+
+from .logger import get_logger
+
+logger = get_logger(__name__)
+
+
+class PartialProgress:
+    def __init__(
+        self, progress: "Progress", partial_start_ratio: float, partial_end_ratio: float
+    ) -> None:
+        self.progress: Final = progress
+        self.partial_start_ratio: Final = partial_start_ratio
+        self.partial_end_ratio: Final = partial_end_ratio
+
+    def update(self, ratio: float) -> None:
+        ratio = min(max(0.0, ratio), 1.0)
+        self.progress.update(
+            self.partial_start_ratio
+            + ratio * (self.partial_end_ratio - self.partial_start_ratio)
+        )
+
+
+class Progress:
+    active_progress_uuid: Optional[str] = None
+
+    def __init__(self, context: Context, *, show_progress: bool) -> None:
+        self.context: Final = context
+        self.show_progress: Final = show_progress
+        self.uuid: Final = uuid4().hex
+        self.last_ratio = 0.0
+
+    def partial_progress(self, partial_end_ratio: float) -> PartialProgress:
+        partial_end_ratio = min(max(0.0, partial_end_ratio), 1.0)
+        return PartialProgress(self, self.last_ratio, partial_end_ratio)
+
+    def update(self, ratio: float) -> None:
+        ratio = min(max(0.0, ratio), 1.0)
+        self.last_ratio = ratio
+        if self.active_progress_uuid != self.uuid:
+            logger.error(
+                "Progress.update() called from different progress active=%s self=%s",
+                self.active_progress_uuid,
+                self.uuid,
+            )
+            return
+
+        if not self.show_progress:
+            return
+
+        if bpy.app.version >= (5, 0):
+            progress_value = ratio * 9999
+        else:
+            # The mouse cursor becomes a four-digit number, and there is an area
+            # where values from 0 to 9999 can be displayed. However, if the
+            # progress rate is directly converted to a number from 0 to 9999, the
+            # last two digits will frequently round-trip, making the progress
+            # difficult to understand. Therefore, only the last two digits display
+            # area is used to show the progress rate as a number from 0 to 99.
+            progress_value = math.floor(ratio * 99)
+
+        self.context.window_manager.progress_update(progress_value)
+
+
+@contextmanager
+def create_progress(
+    context: Context, *, show_progress: bool = True
+) -> Iterator[Progress]:
+    saved_progress_uuid = Progress.active_progress_uuid
+    try:
+        if show_progress and Progress.active_progress_uuid is None:
+            context.window_manager.progress_begin(0, 9999)
+        progress = Progress(context, show_progress=show_progress)
+        Progress.active_progress_uuid = progress.uuid
+        yield progress
+    finally:
+        Progress.active_progress_uuid = saved_progress_uuid
+        if show_progress and Progress.active_progress_uuid is None:
+            context.window_manager.progress_end()