Summary

Improves Poco::Zip handling of non-standard ZIP archives that previously caused exceptions during parsing.

Changes

1. Handle duplicate entries

Archives containing duplicate file entries no longer throw assertions. Instead, duplicate entries are renamed with a .duplicate-N suffix to preserve all data:

file.txt
file.txt.duplicate-1
file.txt.duplicate-2

2. Extended CompressionMethod enum

Added support for recognizing additional compression methods defined in the ZIP specification:

• CM_BZIP2 (12)
• CM_LZMA (14)
• CM_ZSTD (93)
• CM_XZ (95)
• CM_PPMD (98)
• CM_AES (99)
• And others

Note: These methods are recognized during parsing but decompression still only supports CM_STORE and CM_DEFLATE. Attempting to decompress unsupported methods throws a descriptive exception with the method ID and filename.

3. Removed compression method assertion during parsing

Previously, poco_assert (... < ZipCommon::CM_UNUSED) prevented parsing archives with compression methods > 10. This assertion is removed; validation now happens at decompression time with a clear error message.

4. Fixed data descriptor detection

searchCRCAndSizesAfterData() now checks bit 3 of general purpose flags for all compression methods, not just CM_STORE and CM_DEFLATE.

Testing

All 25 Zip tests pass.

Closes #4651