Document exporting individual panels from a dashboard (CSV report from a Discover session panel)

Start with dashboards/sharing.md and save-open-search.md, then review the referenced Kibana reporting panel-action path and verify the current UI label. Document how to generate immediate and scheduled CSV reports from a Discover session panel, and distinguish that action from visualization-data Download CSV; done when both export paths and their scopes are clear.

Summary

Dashboard export documentation covers dashboard-level exports but not per-panel exports. In particular, generating a CSV report from a Discover session panel is undocumented, even though it's a distinct action from the visualization-data "Download CSV" that the docs already describe.

Share and export dashboards lists three export paths:

• Export as PDF or PNG (whole dashboard)
• Download visualization data as CSV (#download-csv) — inline download of the data behind a Lens/chart/table visualization
• Export JSON (dashboard definition)

There is no entry for exporting the contents of an individual Discover session panel as a CSV report. That panel action is a separate mechanism: it uses the reporting system (immediate or scheduled), it's labeled Generate CSV report in the UI (not Download CSV), and it works on saved-search / Discover session panels rather than visualizations.

Why this needs docs

• A dashboard user with a Discover session panel who wants a CSV has no documented path. sharing.md#download-csv explicitly scopes itself to visualizations ("chart and table visualizations that expose tabular data, typically those created with Lens"), so it doesn't cover them.
• The two mechanisms are easy to conflate because both surface CSV. Clarifying the distinction (visualization data download vs. Discover session panel CSV report) would help.
• save-open-search.md "Manage Discover session panels on a dashboard" documents editing and tab selection for these panels but says nothing about exporting them.

Suggested scope

• Add a "Generate a CSV report from a Discover session panel" entry/section to Share and export dashboards, or cross-reference it from there, covering immediate and scheduled reports.
• Clarify the difference between Download CSV (visualization data) and Generate CSV report (Discover session panel, reporting path).
• Verify UI labels at HEAD before drafting: the panel action is reporting.share.panelAction.generateCsvPanelTitle → Generate CSV report (confirmed in elastic/kibana at time of filing).

Context / related

• Split out from #7632 / elastic/docs-content#7673, which documents that CSV reports of ES|QL Discover sessions and Discover session panels apply the currently selected variable control values. That PR intentionally scoped the dashboard-panel export documentation out, since it's a broader pre-existing gap.
• Implementation reference for the panel action: src/platform/packages/private/kbn-reporting/get_csv_panel_actions/ in elastic/kibana.