docs(deployment): add v1.1.x to v1.2.0 search-backend transition callouts

[brandonrc]

Summary

The Meilisearch to OpenSearch migration is a v1.2.0 breaking change (artifact-keeper#830, #865). The currently published documentation correctly describes the v1.1.x stable behavior (Meilisearch). Until v1.2.0 ships, users on stable should not see OpenSearch as the documented backend, but they should be aware the change is coming so they can plan.

This issue adds version-aware callouts to deployment guides without flipping the primary content.

Scope

Add a callout (Starlight :::note or similar) on each affected page noting:

Meilisearch is the search backend in v1.1.x. v1.2.0 will replace it with OpenSearch. See the migration notes in the v1.2.0 CHANGELOG.

Pages to touch:

• src/content/docs/docs/deployment/helm.mdx (service list L12, mermaid diagram L72)
• src/content/docs/docs/deployment/docker.mdx (service table around L58, troubleshooting section L224 to L285)
• src/content/docs/docs/deployment/windows.mdx (Optional: Meilisearch section)
• src/content/docs/docs/deployment/aws.mdx (diagram and config blocks)

Acceptance criteria

• Each affected page has a v1.2.0 transition callout near the top of any Meilisearch reference.
• Callouts link to the v1.2.0 CHANGELOG entry once it lands (or to artifact-keeper#830 in the meantime).
• No primary content flipped from Meilisearch to OpenSearch on these pages (that is tracked separately).

Related

• artifact-keeper#830 OpenSearch migration
• artifact-keeper#865 v1.2.0 CHANGELOG
• Sibling issue: docs flip when v1.2.0 ships (umbrella tracking)