Close workspace search with the Escape key

Is your feature request related to a problem? Please describe.

In the workspace, once the search UI is open (either Search layers or Search on canvas), there is no keyboard way to dismiss it — closing requires reaching for the close (X) control with the mouse.

Pressing Escape is the standard convention in most tools and operating systems for dismissing panels, dialogs, and overlays. Not supporting it here breaks a deeply ingrained habit and interrupts keyboard-first workflows.

This is a small UX enhancement complementary to the toggle behaviour described in #9528, and sits on top of the search work landing in the 2.16 milestone (related context: PR #8899).

Panels in scope The following panels have been identified as missing Escape-to-close support:

• Search (Search layers / Search on canvas) — related to #9528 and PR #8899
• History
• Shortcuts

Other panels in the workspace should be audited and brought into alignment with this behaviour where applicable.

Describe the solution you'd like

When the search panel is open and focus is inside it, pressing Escape should close the panel (same effect as clicking the X) and return focus to the canvas.

• If focus is inside the search panel, Escape closes search and returns focus to the canvas.
• If focus has already moved outside the panel (e.g. back to the layers list), Escape should behave as it normally does in that context — it must not close search unexpectedly.

How to verify: open the workspace, open search with its shortcut, place the cursor in the search input, and press Escape — the panel should dismiss. Confirm that pressing Escape while focus is outside the panel does not affect it.