feat(vrm_mesh_tools): Add standalone VRM mesh tools addon with separation and UV merging

- Add VRM Mesh Tools addon as independent Blender extension with complete functionality
- Implement Body Mesh Separator operator to isolate non-skin materials (CLOTH, etc.) from Body mesh
- Implement UV Edge Merger operator to convert triangles to quads based on UV coordinates
- Add comprehensive UI panel in sidebar with material list and operation buttons
- Include UV edge data JSON files for 10 VRM material types (Body, Face, Eyes, Hair, etc.)
- Add detailed README with installation instructions, usage guide, and compatibility notes
- Configure addon manifest for Blender 4.2+ with proper namespace isolation (vrm_mesh_tools)
- Ensure full compatibility with official VRM addon through independent naming conventions
- Add utility functions for mesh operations, material detection, and JSON data loading

vrm_mesh_tools/__init__.py

@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: MIT
+# VRM Mesh Tools - Standalone mesh separation and UV edge merging tools
+
+bl_info = {
+    "name": "VRM Mesh Tools",
+    "author": "VRM Mesh Tools Contributors",
+    "version": (1, 0, 0),
+    "blender": (4, 2, 0),
+    "location": "View3D > Sidebar > VRM Tools",
+    "description": "Standalone mesh separation and UV edge merging tools for VRM models",
+    "warning": "",
+    "support": "COMMUNITY",
+    "category": "Mesh",
+}
+
+from .ops import (
+    VRM_TOOLS_OT_separate_non_skin_faces,
+    VRM_TOOLS_OT_merge_uv_edges,
+)
+from .panel import (
+    VRM_TOOLS_PT_mesh_separator,
+)
+
+# Classes to register
+_classes: list[type] = [
+    VRM_TOOLS_OT_separate_non_skin_faces,
+    VRM_TOOLS_OT_merge_uv_edges,
+    VRM_TOOLS_PT_mesh_separator,
+]
+
+
+def register() -> None:
+    """Register all classes for the addon."""
+    import bpy
+
+    for cls in _classes:
+        bpy.utils.register_class(cls)
+
+
+def unregister() -> None:
+    """Unregister all classes for the addon."""
+    import bpy
+
+    for cls in reversed(_classes):
+        bpy.utils.unregister_class(cls)