Create the background effects with the app's view model

- AppViewModel creates them, next to its media devices, as review asked;
  BackgroundEffectsProvider takes them as a prop rather than building
  them in an effect.
- The component build, which has no AppViewModel of its own, now makes one
  in the effect that made its media devices, so both builds get their
  state the same way.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/room/CallView.test.tsx

@@ -50,6 +50,7 @@ import {
   mockMediaDevices,
   mockRtcMembership,
   MockRTCSession,
+  testScope,
 } from "../utils/test";
 import { CallView } from "./CallView";
 import { GroupCallErrorBoundary } from "./GroupCallErrorBoundary";
@@ -61,7 +62,10 @@ import {
 } from "../HostBridge";
 import { type JoinCallData } from "../widget";
 import { MatrixRTCTransportMissingError } from "../utils/errors";
-import { BackgroundEffectsProvider } from "../livekit/BackgroundEffectsContext";
+import {
+  BackgroundEffectsProvider,
+  createAppBackgroundEffects,
+} from "../livekit/BackgroundEffectsContext";
 import { MediaDevicesContext } from "../MediaDevicesContext";
 import { constant } from "../state/Behavior";
 
@@ -193,7 +197,9 @@ function createCallView(
       <HostBridgeProvider value={hostBridge}>
         <TooltipProvider>
           <MediaDevicesContext value={mockMediaDevices({})}>
-            <BackgroundEffectsProvider>
+            <BackgroundEffectsProvider
+              effects={createAppBackgroundEffects(testScope())}
+            >
               {options.withErrorBoundary ? (
                 <GroupCallErrorBoundary recoveryActionHandler={vi.fn()}>
                   {callView}

src/room/InCallView.test.tsx

@@ -31,6 +31,7 @@ import {
   mockRemoteParticipant,
   mockRtcMembership,
   type MockRTCSession,
+  testScope,
 } from "../utils/test";
 import { E2eeType } from "../e2ee/e2eeType";
 import {
@@ -49,7 +50,10 @@ import { MediaDevicesContext } from "../MediaDevicesContext";
 import { type MediaDevices as ECMediaDevices } from "../state/MediaDevices";
 import { AppBar } from "../AppBar";
 import { type MatrixInfo } from "./VideoPreview";
-import { BackgroundEffectsProvider } from "../livekit/BackgroundEffectsContext";
+import {
+  BackgroundEffectsProvider,
+  createAppBackgroundEffects,
+} from "../livekit/BackgroundEffectsContext";
 import { initializeWidget } from "../widget";
 import { RootElementProvider } from "../RootElementContext";
 
@@ -242,7 +246,9 @@ describe("ActiveCall", () => {
     const { findByTestId } = render(
       <BrowserRouter>
         <MediaDevicesContext value={mediaDevices}>
-          <BackgroundEffectsProvider>
+          <BackgroundEffectsProvider
+            effects={createAppBackgroundEffects(testScope())}
+          >
             <TooltipProvider>
               <RoomContext value={mockLivekitRoom({ localParticipant })}>
                 <ActiveCall
@@ -292,7 +298,9 @@ describe("ActiveCall", () => {
         <BrowserRouter>
           <RootElementProvider value={root}>
             <MediaDevicesContext value={mediaDevices}>
-              <BackgroundEffectsProvider>
+              <BackgroundEffectsProvider
+                effects={createAppBackgroundEffects(testScope())}
+              >
                 <TooltipProvider>
                   <RoomContext value={mockLivekitRoom({ localParticipant })}>
                     <ActiveCall