[feature request] Move Meshery from Sandbox to Incubating

Meshery has moved from Sandbox to Incubating (effective 2026-09-14, TOC vote passed).

Please update devstats to reflect the new maturity level for the Meshery project.

**Project:** Meshery
**From:** Sandbox
**To:** Incubating
**Effective date:** 2026-09-14

**Tracking issue:** cncf/toc#2302
**TOC vote PR:** cncf/toc#2284
**Devstats URL:** https://meshery.devstats.cncf.io/

Related cross-repo PRs (for reference):
- Landscape: cncf/landscape#5144
- Clomonitor: cncf/clomonitor#1930
- Artwork: cncf/artwork#680
- Maintainer spreadsheet: cncf/foundation#1522