v2.1.0 — per-stream Unity 6 databases + auto-updates

What's new

• Per-minor-stream Unity 6 databases: UNITY_VERSION now accepts streams like 6000.3 (and full versions like 6000.3.8f1 map to their stream). Each active stream gets its own weekly-rebuilt database; the generic 6 database remains as fallback and default.
• Automatic database updates: cached databases are freshness-checked against the release on startup and re-downloaded when a newer build is available — no reinstall needed.
• Weekly automated rebuilds: new Unity patch releases are detected every Monday and databases are rebuilt automatically per active stream.
• License: relicensed from PolyForm Noncommercial to MIT.
• macOS Unity installs are now supported for local ingestion (Unity.app/Contents/Resources/Scripting/Managed).