Accessibility pass on search, Offline Maps and turn-by-turn panels

The new Apple-style panels (search, Offline Maps, turn-by-turn cards) need an accessibility pass.

Scope

• Search: aria-activedescendant for the highlighted row, and announcing results count and selection through a live region. Focus returns to the field after closing a card.
• Offline Maps panel: focus management when it opens and closes; buttons with accessible names ("Pause San Francisco download"); download progress as role="progressbar" with values.
• Area picker: corner handles reachable and movable by keyboard (arrow keys), with an accessible description of the selected area and its estimated size.
• Turn-by-turn: the banner as a polite live region; End and mute buttons labelled.
• Motion: honour prefers-reduced-motion for fly-to animations and pin transitions.
• Contrast: check both themes.
• Add tests with an accessibility checker where feasible.