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

CHANGELOG_NON_ASCII_FIX.md

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+# Fix for Garbled Japanese/Non-ASCII Text in Dropdowns
+
+## Problem
+Japanese, Korean, Chinese, and other non-ASCII characters were displaying as garbled/corrupted text in dropdown menus for:
+- Armature selection in Quick Access panel
+- Mesh selection in Visemes panel
+
+This is a known issue with Blender's EnumProperty system when using dynamic callbacks that return Unicode strings.
+
+## Root Cause
+Blender's EnumProperty RNA system can have encoding issues when:
+1. The enum items function is called multiple times with changing data
+2. Unicode strings in display names aren't properly cached
+3. The internal C API receives the same Python string object in different states
+
+## Solution
+Implemented proper caching with invalidation for EnumProperty items:
+
+### Changes Made
+
+1. **core/common.py** - Enhanced `get_armature_list()` function
+   - Added cache key based on (name, pointer) tuples
+   - Cache is invalidated only when actual objects change
+   - Prevents Blender from re-encoding strings on every access
+   - Added `clear_enum_caches()` helper function
+
+2. **core/properties.py** - Enhanced `get_mesh_objects()` function  
+   - Added same caching mechanism as armature list
+   - Cache key based on mesh objects (name, pointer)
+   - Stable cache prevents encoding corruption
+
+3. **core/common.py** - `get_mesh_from_identifier()` helper
+   - Converts safe identifier back to mesh object
+   - Handles both new format (`MESH_{pointer}`) and legacy format
+   - Returns None if mesh not found
+
+4. **ui/visemes_panel.py** - Updated mesh retrieval
+   - Uses `get_mesh_from_identifier()` instead of direct lookup
+
+5. **functions/visemes.py** - Updated all mesh access points
+   - All operators now use the helper function consistently
+
+## Technical Details
+
+### ASCII-Safe Identifiers
+- Dropdown identifier: `ARM_{memory_pointer}` or `MESH_{memory_pointer}` (ASCII-safe, unique)
+- Dropdown display: Original object name (preserves Unicode characters)
+- Backwards compatibility: Falls back to direct name lookup
+
+### Caching Strategy
+The cache uses function attributes to store:
+- `_cache_key`: Tuple of (name, pointer) for all relevant objects
+- `_cached_items`: The actual list of enum items
+
+Cache is invalidated when:
+- Objects are added/removed
+- Objects are renamed
+- Object pointers change (object recreated)
+
+This ensures Blender's RNA system receives the exact same Python string objects on subsequent calls, preventing encoding corruption.
+
+## Testing
+
+To verify the fix works:
+1. Create armature/mesh objects with Japanese/Korean/Chinese names (e.g., "アバター", "아바타", "化身")
+2. Open Quick Access panel - armature dropdown should display correctly
+3. Open Visemes panel - mesh dropdown should display correctly
+4. Select items - operations should work with the selected objects
+5. Rename objects - dropdowns should update and still display correctly
+
+## Related Files
+- `core/properties.py` - Property definitions and mesh enumeration
+- `core/common.py` - Common utility functions and armature enumeration
+- `ui/visemes_panel.py` - Visemes UI panel
+- `ui/quick_access_panel.py` - Quick Access UI panel
+- `functions/visemes.py` - Viseme operators
+
+## Note on prop_search
+The `prop_search` widget used for shape key/bone selection inherently handles non-ASCII characters correctly since it searches Blender's internal data structures directly, not custom enum properties.