Earpiece switcher and overlay (#3347)

* Add a global control for toggling earpiece mode

This will be used by Element X to show an earpiece toggle button in the header.

* Add an earpiece overlay


* Fix header
The header needs to be passed forward as a string to some components and as a bool (hideHeader) to others.
Also use a enum instead of string options.

* fix top clipping with header


* hide app bar in pip

* revert android overlay app_bar

* Modernize AppBarContext

* Style header icon color as desired and switch earpice/speaker icon

* fix initial selection when using controlled media

* Add "Back to video" button

* fix tests

* remove dead code

* add snapshot test

* fix back to video button

* Request capability to learn the room name

We now need the room name in order to implement the mobile (widget-based) designs with the app bar.

* Test the CallViewModel output switcher directly

---------

Co-authored-by: Timo <toger5@hotmail.de>

src/room/EarpieceOverlay.tsx

@@ -0,0 +1,42 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { type FC } from "react";
+import { BigIcon, Button, Heading, Text } from "@vector-im/compound-web";
+import { EarpieceIcon } from "@vector-im/compound-design-tokens/assets/web/icons";
+import { useTranslation } from "react-i18next";
+
+import styles from "./EarpieceOverlay.module.css";
+
+interface Props {
+  show: boolean;
+  onBackToVideoPressed?: (() => void) | null;
+}
+
+export const EarpieceOverlay: FC<Props> = ({ show, onBackToVideoPressed }) => {
+  const { t } = useTranslation();
+  return (
+    <div className={styles.overlay} data-show={show}>
+      <BigIcon className={styles.icon}>
+        <EarpieceIcon aria-hidden />
+      </BigIcon>
+      <Heading as="h2" weight="semibold" size="md">
+        {t("earpiece.overlay_title")}
+      </Heading>
+      <Text>{t("earpiece.overlay_description")}</Text>
+      <Button
+        kind="primary"
+        size="sm"
+        onClick={() => {
+          onBackToVideoPressed?.();
+        }}
+      >
+        {t("earpiece.overlay_back_button")}
+      </Button>
+    </div>
+  );
+};