* Preserve truncating FileIO mode and sync canonical IO compatibility
Keep truncation metadata in both host backends so writable update streams report wb+. Synchronize the complete final CPython _pyio module and two complete canonical mode test definitions through scripts/update_lib.
Assisted-by: OpenAI Codex: model identifier unavailable
* Update gzip, tarfile, and shutil from CPython 3.15
Regenerate six Lib files using scripts/update_lib from CPython d220409a13b77de7a6c30abe16ea90db01528edc. Preserve upstream tests without agent-added marks.
Assisted-by: OpenAI Codex:model version unavailable
* Sync canonical spooled tempfile mode expectation
Copy the complete TestSpooledTemporaryFile.test_properties definition from CPython 3.15.0 final d220409a using scripts/update_lib copy-test. Preserve all surrounding test content and existing markers.
Assisted-by: OpenAI Codex:model version unavailable
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Co-authored-by: youknowdot <336763669+youknowdot@users.noreply.github.com>
