chore(catalog): bump v-model extension to v0.6.0 (#2399)

Update v-model extension entry in community catalog to reflect the v0.6.0
release: https://github.com/leocamello/spec-kit-v-model/releases/tag/v0.6.0

Highlights of v0.6.0:
- Domain Overlay Architecture (9 overlay manifests; automotive, medical,
  aerospace, general)
- ID Lifecycle Model (Proposed -> Active -> Deprecated -> Removed)
- Standards enrichment across all 11 commands (IEEE 1012:2016, ISO
  25010:2023, ISO 42030:2019, ISO 12207:2017, IEEE 1016, IEEE 29148,
  ISO 29119-4, ISO 14971, DO-178C, ARP4761A, INCOSE SE Handbook)
- Aerospace DO-178C support: Flight Warning Computer DAL-A golden fixture
- Test infrastructure: fixtures reorganized; +11 LLM-as-judge evals (42 -> 53)

Command count remains 14 (no new commands added in this release).
Stars updated to live count (21) from GitHub API.