Add support for new naming format for metadata json file

[0xForkh]

Google Takeout Metadata Handling

Fix for #448

Google Takeout now uses .supplemental-metadata.json files instead of plain .json files.
These filenames can be truncated due to length limits, resulting in variations like:

• .supplemental-metadata.json (full)
• .s.json (shortest truncation)
• .supple.json, .suppleme.json (partial truncations)

This commit:

• Updates JSON file matching to check for supplemental-metadata patterns
• Handles truncated filename variations
• Maintains backward compatibility with original .json format
• Adds comprehensive tests for all format variations

Fixes compatibility with newer Google Takeout exports while preserving support for older formats.