- Implement ProPlaylistReader::read() following ProFileReader pattern
- ZIP handling: fix headers with Zip64Fixer, extract data + embedded files
- Comprehensive error handling: missing file, empty file, invalid ZIP, missing data entry
- Temp file cleanup in finally block (no leaks on error paths)
- 11 tests, 31 assertions — all pass
- Verified with all 4 .proplaylist test files
Task 7 of proplaylist-module plan complete
