0.4.6: FileTreeStore and Redis fixes

What's Changed

• Fix FileTreeStore disk-space leak, get() race, and RedisStore username passthrough by @strawgate in #370
• Mention Pydantic Logfire in README by @strawgate in #372
• Split oldest-dependency CI coverage by @strawgate in #374
• Prepare 0.4.6 release by @strawgate in #373

Full Changelog: 0.4.5...0.4.6