chore: automated code quality fixes

[reekeer]

Automated fixes from reekeerBot

[reekeer]

reekeer[bot] Report

Ruff issues

• src/sigdb/internal/groups.py:100 Use key in dict instead of key in dict.keys()

Pyright issues

• src/sigdb/compression/zstd.py Type of "cctx" is unknown
• src/sigdb/compression/zstd.py Type of "ZstdCompressor" is unknown
• src/sigdb/compression/zstd.py Type of "compress" is unknown
• src/sigdb/compression/zstd.py Return type is unknown
• src/sigdb/compression/zstd.py Type of "dctx" is unknown
• src/sigdb/compression/zstd.py Type of "ZstdDecompressor" is unknown
• src/sigdb/compression/zstd.py Type of "decompress" is unknown
• src/sigdb/compression/zstd.py Return type is unknown
• src/sigdb/crypto/ed25519.py Return type, "tuple[Unknown, Unknown, Unknown]", is partially unknown
• src/sigdb/crypto/ed25519.py Return type, "tuple[Unknown, Unknown, Unknown]", is partially unknown
• src/sigdb/crypto/ed25519.py Type of "SigningKey" is unknown
• src/sigdb/crypto/ed25519.py Type of "_VerifyKey" is unknown
• src/sigdb/crypto/ed25519.py Type of "_BadSignatureError" is unknown
• src/sigdb/crypto/ed25519.py Type of "generate" is unknown
• src/sigdb/crypto/ed25519.py Type of "encode" is unknown