[Task] Az.Marketplace PowerShell module - moving from Preview to GA #30266

Summary

Track moving Az.Marketplace from Preview to GA, targeting the November sprint.

Background

Az.Marketplace has shipped only pre-1.0 preview versions since its first release
(0.1.0 - the first preview release), most recently 0.6.0. There has never been a GA
(1.0.0+) release of this module.

A GA PR is already in flight: #30265 ("GA Az.Marketplace"). This task tracks getting that work
(and any remaining GA-readiness items) landed in the November sprint.

Scope / Ask

• Review and close out PR GA Az.Marketplace #30265
• Confirm GA readiness checklist is complete (breaking changes reviewed, docs/help up to date,
  versioning bumped to 1.0.0, changelog updated)
• Target: land in the November sprint

Target sprint

November 2026 sprint.

cc Norizhang