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/logger.py

@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: MIT OR GPL-3.0-or-later
+import logging
+import sys
+from collections.abc import Mapping
+from os import environ
+from types import TracebackType
+from typing import TYPE_CHECKING, Optional, Union
+
+import bpy
+
+# https://github.com/python/typeshed/issues/7855
+if TYPE_CHECKING or sys.version_info >= (3, 11):
+    LoggerAdapter = logging.LoggerAdapter[logging.Logger]
+else:
+    LoggerAdapter = logging.LoggerAdapter
+
+
+class VrmAddonLoggerAdapter(LoggerAdapter):
+    def log(
+        self,
+        level: int,
+        msg: object,
+        *args: object,
+        exc_info: Union[
+            None,
+            bool,
+            Union[
+                tuple[type[BaseException], BaseException, Optional[TracebackType]],
+                tuple[None, None, None],
+            ],
+            BaseException,
+        ] = None,
+        stack_info: bool = False,
+        stacklevel: int = 1,
+        extra: Optional[Mapping[str, object]] = None,
+        **kwargs: object,
+    ) -> None:
+        level_name = logging.getLevelName(level)
+        super().log(
+            level,
+            f"[VRM Add-on:{level_name}] {msg}",
+            *args,
+            exc_info=exc_info,
+            stack_info=stack_info,
+            stacklevel=stacklevel,
+            extra=extra,
+            **kwargs,
+        )
+
+
+# https://docs.python.org/3.7/library/logging.html#logging.getLogger
+def get_logger(name: str) -> LoggerAdapter:
+    logger = logging.getLogger(name)
+    if bpy.app.debug or environ.get("BLENDER_VRM_LOGGING_LEVEL_DEBUG") == "yes":
+        logger.setLevel(min(logging.DEBUG, logger.getEffectiveLevel()))
+    else:
+        logger.setLevel(max(logging.INFO, logger.getEffectiveLevel()))
+    return VrmAddonLoggerAdapter(logger, {})