compression: report malformed payloads as invalid_argument

[Yong-yuan-X]

Summary

• report malformed gzip and zstd compressed payloads as invalid_argument instead of internal
• apply the error-code change consistently across gzip/zstd bad header, truncated stream, CRC mismatch, size mismatch, and decoder failure paths
• add regression coverage for malformed gzip/zstd payload error codes
• document the observable error-code change in the changelog

Closes #139.

Testing

• cargo test -p connectrpc compression

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