Number output files and folders instead of overwriting

Pack now writes <Name>.cache, or <Name>.cache.1, .2, ... if that file
already exists (replaces the fixed .cache.new name). Unpack writes each
target folder under ARCANE_DUMP the same way, e.g. COBJECTS.1. The
output folder is created only after the cache loads, so a missing cache
does not leave an empty numbered folder.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mbEditorPro2.0/arcane/util/__init__.py

@@ -6,5 +6,5 @@
 #                Magicbane Emulator Project © 2013 - 2022
 #                           www.magicbane.com
 
-from .ArcFileCache import load_cache_file, save_cache_file
+from .ArcFileCache import load_cache_file, save_cache_file, next_available_path
 from .ResStream import ResStream