When a type (folders, settings, variables, resources, triggers) is NOT
configured in specificItems, branch-specific files of that type should
be ignored and only base files used.
Added isItemTypeConfigured() function to distinguish between:
- Type not configured → skip branch-specific file, use base file
- Type configured but doesn't match pattern → skip branch-specific file
- Type configured and matches → use branch-specific file
Added comprehensive tests to prevent regression.
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>