Add BZIP2, LZMA, and ZSTANDARD decompression support to NetZipFile

[Copilot]

NetZipFile only supported STORED (0) and DEFLATE (8), leaving three compression methods supported by Python's zipfile module unhandled.

Changes

• New reader classes — _Bzip2Reader (method 12), _LzmaReader (method 14), and _ZstdReader (method 93), each following the same buffered io.RawIOBase pattern as the existing _DeflateReader
• LZMA header handling — _LzmaZipDecompressor parses the 4-byte ZIP LZMA header (version + properties size), extracts LZMA1 filter properties, then initializes lzma.LZMADecompressor(FORMAT_RAW, ...) — mirrors CPython's own zipfile.LZMADecompressor
• ZSTD availability guard — compression.zstd is only available on Python 3.14+; raises RuntimeError at runtime if the entry requires ZSTD on an older interpreter
• _open_entry_data dispatch — extended elif chain to route methods 12, 14, and 93 to the new readers
• Tests — one test per new method; ZSTD test is skipif Python < 3.14; helper zip-builder functions added alongside the existing _create_deflate_zip

Original prompt

Currently #file:netzipfile.py supports only the STORED and DEFLATE compression methods: #file:netzipfile.py:355-370

Please add support for all compression methods that Python's latest stable/released version of the zipfile module supports. Consult the CPython source code if unsure.

Related automated tests, to extend:

• #file:test_netzipfile.py:14-41

Suggest implement new compression methods similar to how DEFLATE support was added.

The user has attached the following file paths as relevant context:

• src/crystal/util/netzipfile.py
• .github/copilot-instructions.md

Created from VS Code.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.