Summary
The Search tab in the secondary panel of the Agents window currently shows a blank content area when there is no query or results. It should have an empty state that matches the Browser tab's empty state styling but explains that this tab is for searching across files.
This issue shares two prototype variants (built in Code OSS, not mockups) and a UserTesting study to help us pick a direction.
Prototypes
Both variants reuse the same visual tokens as the Browser tab empty state, are gated behind an experimental setting (search.searchEditor.emptyState), and appear only when there is no query and no results. The demos show the full Agents window for context (chat pane, Search panel, Files pane), and the empty state correctly hides while typing and returns when the query is cleared.
Variant A - Centered (mirrors the Browser empty state)
A centered search icon, a Search title, and a one line subtitle: "Search for text across files in your workspace."
▶ Full quality MP4: https://github.com/microsoft/vscode/blob/eli/search-tab-empty-state-demo/demo/search-tab-empty-state/variant-A-centered.mp4
