[Hosted agents 12] Publish documentation and the validated umbrella release

[placerda]

Summary

Document the validated hosted-agent modes and prepare the GPT-RAG umbrella release using the exact tested component combination.

Why will we implement this?

• Problem / opportunity: Preview status, deployment choices, authorization, networking, migration, and rollback must be clear before users can adopt hosted mode safely.
• Business value / outcome: Operators receive a supportable opt-in feature with complete recovery guidance and traceable versions.
• Success metrics (how we know it worked): Published docs match shipped behavior; changelog and GitHub Release notes contain the full manifest-derived version table and sanitized validation evidence.

What does it do? (Functional Overview)

• Core behavior: Document classic/hosted modes, optional panel, strategy matrix, managed Conversations, identity/security, private build constraints, costs, migration, operations, and rollback; prepare release artifacts.
• Data collection / storage needs: Do not publish private validation environment/resource-group names.
• Data analysis / reporting needs: Include exact validation evidence and component versions.
• Nice to have (stretch goals): Architecture and mode-selection diagrams.

Components

• Components (check all that apply):
  • gpt-rag-orchestrator
  • gpt-rag-ingestion
  • gpt-rag-ui
  • gpt-rag-mcp

Dependencies and acceptance criteria

• Depends on: [Hosted agents 10] Prove document-level authorization through the hosted path #591 and [Hosted agents 11] Validate private networking, image build, and version rollback #597.
• User-facing docs are updated on the docs branch.
• CHANGELOG.md and release notes agree on every manifest.json component and ailz_tag.
• Classic remains the documented default/fallback and hosted mode is identified as preview where applicable.
• Human approval is required before tag/release publication.

[placerda]

Release scope update

The first hosted-agent preview will publish hosted/no-panel only. DEPLOY_ADMINISTRATIVE_PANEL=false is required; panel completion moved to #611. Release preparation remains blocked on UI #87 and umbrella #610 receiving required formal reviews, compatible component publication with explicit human approval, and one minimal hosted/no-panel security/runtime validation. The published docs and notes must not claim hosted/panel support.