Share a Discover link that opens a specific document

## Summary

Discover can put an open document flyout in the URL. Recipients land on that document instead of only the surrounding query. The flyout header adds Share direct link. Session Share URLs can include the open document and warn when a relative time range might hide it. Classic queries work. ES|QL works for non-transformational queries that include `METADATA _id, _index`. Docs still describe View single document and session-level Share only.

**Why this needs docs:** This is a user-facing Share direct link on the document flyout. Existing share docs cover sessions, not a specific document.

## Resources

- PR [#282175](https://github.com/elastic/kibana/pull/282175) — [Discover] Add doc viewer deep link support

Screenshots from PR


## Availability

| Channel | Details |
|---------|---------|
| **Stack** | v9.6.0 |
| **Serverless** | Aug 31–Sep 4 |
| **Feature flag** | None — active by default |

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*Created with [Docs Quest Scanner](https://github.com/florent-leborgne/docs-quest-scanner) by @florent-leborgne*

## Suggested edits

[Explore fields and data with Discover](https://www.elastic.co/docs/explore-analyze/discover/discover-get-started) > Explore individual result or document details in depth
- **What the docs say:** Click the expand icon to open a flyout with the document details. To navigate to a view of the document that you can bookmark and share, select View single document.
- **What to add:** Add Share direct link in the flyout header. Say the link reopens that document, uses an absolute time range, and works for classic queries and non-transformational ES|QL with `METADATA _id, _index`. Note that STATS or KEEP queries cannot be linked. Applies from 9.6.0 and in serverless.

[Reporting and sharing](https://www.elastic.co/docs/explore-analyze/report-and-share) > Share with a direct link
- **What the docs say:** You can share direct links to saved Discover sessions, dashboards, and visualizations. When applicable, you can choose a relative or an absolute time range.
- **What to add:** Mention that an open Discover document can be included in the shared URL. Point to Share direct link on the flyout. Note the warning when a relative time range might exclude the document. Applies from 9.6.0 and in serverless.