Add zvec to Database section

[chinaux]

Project: zvec

Zvec is an open-source embedded vector database by Alibaba Tongyi Lab, bringing SQLite-like simplicity to vector search. It runs in-process with zero external dependencies — just pip install zvec.

Why it belongs here

• ✅ Python-first: pip install zvec, full Python SDK (3.10–3.14)
• ✅ Actively maintained: latest release v0.5.1 (June 24, 2026)
• ✅ Production-ready: built on Alibaba battle-tested Proxima engine
• ✅ 12,500+ GitHub stars (Rising Star tier, 5x the 5,000-star threshold)
• ✅ Clear README with examples and documentation
• ✅ Distinct value: fills the "SQLite of vector databases" niche — embedded, serverless, zero-config, unlike existing client-server entries
• ✅ Repository age: open-sourced Feb 2026 (> 30 days)
• ✅ Similar precedent: chromadb is already listed in this section