Follow-up to #4354.
Keep Healthcheck and the AI assistant usable with assistive technology when both panels are open. Their independent opening and closing must preserve access to the active panel and its controls.
Acceptance criteria:
- Check both opening orders, closing either panel, reopening and reload.
- Visible active content remains represented in the accessibility tree; opening a second panel must not make both panels inaccessible.
- Keyboard focus, dismissal and return focus work consistently, with accessible names for the relevant controls.
- Add browser coverage for both opening orders and a successful recovery after either panel closes.
Follow-up to #4354.
Keep Healthcheck and the AI assistant usable with assistive technology when both panels are open. Their independent opening and closing must preserve access to the active panel and its controls.
Acceptance criteria: