feat: Add KoikatsuBlenderPipeline addon with import/export functionality

- Add core addon files (__init__.py, KKPanel.py, preferences.py, common.py)
- Add import pipeline with armature, mesh, and material modification modules
- Add export pipeline with material baking and FBX preparation utilities
- Add material combiner tool for texture atlas generation and optimization
- Add extras utilities for animation, rigging, and asset management
- Add bone orientation data from better_fbx for accurate skeletal structure
- Add comprehensive documentation and wiki with multi-language support (EN, JP, ZH)
- Add animation library retargeting lists for ARP and Rokoko motion capture
- Add Rigify integration scripts for advanced rigging workflows
- Add shader file (KK Shader V8.0.blend) for material rendering
- Add manifest and license files for addon distribution
- Add changelog documenting version history and improvements
- Initialize complete Blender addon project for Koikatsu character import/export

extras/matcombswitch.py

@@ -0,0 +1,27 @@
+import bpy
+from ..interface.dictionary_en import t
+from .. import common as c
+
+class mat_comb_switch(bpy.types.Operator):
+    bl_idname = "kkbp.matcombswitch"
+    bl_label = "Material combiner switch"
+    bl_description = t('mat_comb_switch_tt')
+    bl_options = {'REGISTER', 'UNDO'}
+
+    def execute(self, context):
+        #toggle textures for the combiner script
+        for obj in [o for o in bpy.data.collections[c.get_name() + '.001'].all_objects if not o.hide_get() and o.type == 'MESH']:
+            for mat in [mat_slot.material for mat_slot in obj.material_slots if mat_slot.material.get('simple')]:
+                nodes = mat.node_tree.nodes
+                #find the image node
+                image_node = None
+                for node in nodes:
+                    if node.type == 'TEX_IMAGE':
+                        image_node = node
+                if image_node:
+                    #toggle light / dark state
+                    image_node.image = nodes['textures'].node_tree.nodes['dark' if image_node.image == nodes['textures'].node_tree.nodes['light'].image else 'light'].image
+            context.view_layer.objects.active = obj
+            bpy.ops.object.material_slot_remove_unused()
+
+        return {'FINISHED'}