Move key encoding to socket api

[bisho]

Motivation / Description

This change enhances the memcache client to handle arbitrarily long keys by implementing automatic key hashing with Blake2b. Previously, keys were limited to 250 bytes (or 187 bytes for binary keys due to base64 encoding).

This was previously implemented in meta-memcache library in python, but supporting it at the socket level makes for a more robust api. The implementation is backwards compatible, and usages can implement their own key encoding if they wish to or they need backwards compatibility. The keys are unmodified as long as they are non-binary and < 187 bytes, which key encoders should guarantee.

Moving the default encoding to rust provides a small performance gains as well.

Changes introduced

• Added Blake2b hashing dependency to automatically hash keys >= 187 bytes into compact 18-byte digests
• Implemented key encoding logic that handles both string and bytes key types, with automatic base64 encoding for binary keys
• Updated all key parameters in function signatures and type hints to accept Union[str, bytes] instead of just bytes
• Modified command building functions to use the new key encoding system that ensures wire keys are always under the 250-byte memcache limit
• Added comprehensive test coverage for key encoding scenarios including short keys, long keys, binary keys, and edge cases
• Updated error messages to reflect that empty keys are rejected rather than "too long" keys, since long keys are now automatically handled

[bisho]

• Raw cmd for special usages #17
• multi-get #16
• Move key encoding to socket api #15 👈 (View in Graphite)
• Add meta command methods to MemcacheSocket #14
• Add MemcacheSocket class and response types with CI tests #13
• Bump version to 0.1.7 and add Python 3.13t support #12
• Refactor parse_header to return structured type and update to Rust 2024 #11
• Bump version to 0.1.6 and optimize performance #9
• Update to PyO3 Bound API #10
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[ethervoid]

@claude review this PR

[xmartinez]

LG!

Added a comment re: test coverage (non blocking).

[bisho]

Merge activity

• Mar 25, 2:26 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Mar 25, 2:26 PM UTC: @bisho merged this pull request with Graphite.