- Added read_png_text_chunks() function that manually parses PNG file structure
- Reads PNG chunks directly instead of relying on png crate's Info struct
- More reliable extraction of tEXt chunks with "chara" keyword
- Added debug logging (eprintln) to help diagnose import issues
- Updated read_character_card_from_png() to use manual parser as primary method
- Fixes "missing 'chara' chunk" error even when chunk exists in file
- Successfully imports both v2 and v3 character cards
