[OAS] Add description and response examples to /api/status

[TinaHeiligers]

Summary

Adds an operation description and response examples to GET /api/status.

kbn-validate-oas flags three errors for missing operation description, missing examples on the 200 response, and missing examples on the 503 response.

This PR adds them.

Note:
The original issue framed this as a discriminator gap at the time of opening the issue.
With recent work, the validator's actual signal is now missing description plus examples.

Fixes #265889
Relates to #256462

How to test this

node scripts/validate_oas_docs.js --skip-printing-issues --path /api/status

Should report 0 errors on both kibana.yaml and kibana.serverless.yaml.

Checklist

• This was checked for breaking HTTP API changes; no breaking changes (additive OAS metadata only).

Identify risks

Low risk: additive OAS metadata describing what the handler already returns.

Risk	Severity	Likelihood	Mitigation
Example payloads diverge from the runtime response shape	Low	Low	Examples mirror fullStatusResponse and are colocated with the route, so future shape changes surface in review

Co-Authored-By: Claude Opus 4.7

[infra-vault-gh-plugin-prod]

Pinging @elastic/kibana-core (Team:Core)

[florent-leborgne]

LGTM for docs

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: da5af31

Failed CI Steps

• FTR Configs #38
• FTR Configs #72
• affected Scout: [ platform / streams_app-serverless-observability_logs_essentials ] plugin

Test Failures

• [job] [logs] FTR Configs #38 / integrations When in the Fleet application and on the Endpoint Integration details page should display the endpoint custom content

Metrics [docs]

✅ unchanged

History

• 💛 Build #437120 was flaky 5effce9
• 💔 Build #437116 failed 7304b48
• 💔 Build #437087 failed 1daeeb1

[kibanamachine]

Starting backport for target branches: 9.4

https://github.com/elastic/kibana/actions/runs/25384526705

[kibanamachine]

💔 All backports failed

Status	Branch	Result
❌	9.4	Backport failed because of merge conflicts You might need to backport the following PRs to 9.4: - [OAS][Detection Engine] Clean up remaining errors (#266228) - Fix OAS validation errors in entity analytics privilege monitoring APIs && Risk Score APIs (#265470) - [OAS] Improve spec descriptions, summaries, examples (#265153) - [Cases][Docs] - Add additional examples and cleanup to openApi (#263617) - [Entity Analytics] Add missing OpenAPI descriptions and examples to p… (#264778)

Manual backport

To create the backport manually run:

node scripts/backport --pr 267355

Questions ?

Please refer to the Backport tool documentation

[kibanamachine]

Friendly reminder: Looks like this PR hasn’t been backported yet.
To create automatically backports add a backport:* label or prevent reminders by adding the backport:skip label.
You can also create backports manually by running node scripts/backport --pr 267355 locally
cc: @TinaHeiligers