Wire the background effects grid to the pipeline

- Footer view model exposes the chosen effect and a setter for it
- The footer names the catalogue: a view model holds no translated text
- The camera menu shows the grid in place of the blur toggle
- Shipped images are numbered, not named, since the art is a stand-in
- Withholding the setter is what renders the section disabled, as with
  the speaker section where no output can be chosen

Exploration for FEATURES_SPEC/2026-09_Background_Effects.md.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

locales/en/app.json

@@ -4,6 +4,9 @@
   },
   "action": {
     "add_background_image": "Add image",
+    "background_effect_blur": "Blur",
+    "background_effect_none": "None",
+    "background_effect_numbered": "Background {{n}}",
     "blur_background": "Blur background",
     "close": "Close",
     "copy_link": "Copy link",

src/components/CallFooter.stories.tsx

@@ -124,6 +124,8 @@ export const Default: Story = {
     toggleScreenSharing: fn(),
     toggleBlur: fn(),
     videoBlurEnabled: true,
+    backgroundEffect: "none",
+    selectBackgroundEffect: fn(),
     hangup: fn(),
     buttonSize: "lg",
     showFooter: true,

src/components/CallFooter.tsx

@@ -7,6 +7,7 @@ Please see LICENSE in the repository root for full details.
 
 import { type FC, type JSX, type Ref, useMemo } from "react";
 import classNames from "classnames";
+import { useTranslation } from "react-i18next";
 
 import LogoMark from "../icons/LogoMark.svg?react";
 import LogoType from "../icons/LogoType.svg?react";
@@ -23,9 +24,11 @@ import {
 } from "../button";
 import styles from "./CallFooter.module.css";
 import {
+  type BackgroundEffectOption,
   MediaMuteAndSwitchButton,
   type MenuOptions,
 } from "./MediaMuteAndSwitchButton";
+import { shippedBackgrounds } from "../livekit/backgroundEffects";
 import { type Behavior } from "../state/Behavior";
 import { type ViewModel } from "../state/ViewModel";
 import { useBehavior } from "../useBehavior";
@@ -57,6 +60,8 @@ export interface FooterActions {
   /** Also controls if the videoMute button is disabled */
   toggleVideo: (() => void) | undefined;
   toggleBlur: (() => void) | undefined;
+  /** Undefined where background processing is unavailable. */
+  selectBackgroundEffect: ((id: string) => void) | undefined;
   toggleScreenSharing: (() => void) | undefined;
   /** Also controls if the settings button is visible */
   openSettings: (() => void) | undefined;
@@ -70,6 +75,8 @@ export interface FooterState {
   videoEnabled: boolean;
   videoBusy: boolean;
   videoBlurEnabled: boolean;
+  /** The chosen background effect, in its stored form. */
+  backgroundEffect: string;
   showFooter: boolean;
 
   /* This is needed for WindowMode = "flat" */
@@ -123,6 +130,7 @@ export const CallFooter: FC<FooterProps> = ({
   children,
   vm,
 }) => {
+  const { t } = useTranslation();
   const asOverlay = useBehavior(vm.asOverlay$);
   const showFooter = useBehavior(vm.showFooter$);
   const hideControls = useBehavior(vm.hideControls$);
@@ -151,8 +159,26 @@ export const CallFooter: FC<FooterProps> = ({
   const selectedAudioOutput = useBehavior(vm.selectedAudioOutput$);
   const selectAudioOutputOption = useBehavior(vm.selectAudioOutputOption$);
   const selectVideoButtonOption = useBehavior(vm.selectVideoButtonOption$);
-  const toggleBlur = useBehavior(vm.toggleBlur$);
+  const backgroundEffect = useBehavior(vm.backgroundEffect$);
-  const videoBlurEnabled = useBehavior(vm.videoBlurEnabled$);
+  const selectBackgroundEffect = useBehavior(vm.selectBackgroundEffect$);
+
+  // The catalogue is named here rather than in the view model: the names are
+  // for reading, and a view model has no business holding translated text.
+  const backgroundEffects = useMemo(
+    (): BackgroundEffectOption[] => [
+      { id: "none", kind: "none", label: t("action.background_effect_none") },
+      { id: "blur", kind: "blur", label: t("action.background_effect_blur") },
+      ...shippedBackgrounds.map((background, i) => ({
+        id: `image:${background.id}`,
+        kind: "image" as const,
+        // Numbered rather than named: the images are stand-ins, and naming
+        // them here would invent names the design has not given them.
+        label: t("action.background_effect_numbered", { n: i + 1 }),
+        imageUrl: background.imagePath,
+      })),
+    ],
+    [t],
+  );
   const buttonSize = useBehavior(vm.buttonSize$);
   const showLogo = useBehavior(vm.showLogo$);
 
@@ -214,8 +240,9 @@ export const CallFooter: FC<FooterProps> = ({
         options={videoOptions}
         selectedOption={selectedVideo}
         onSelect={selectVideoButtonOption}
-        videoBlurToggleClick={toggleBlur}
+        backgroundEffects={backgroundEffects}
-        videoBlurEnabled={videoBlurEnabled}
+        selectedBackgroundEffect={backgroundEffect}
+        onSelectBackgroundEffect={selectBackgroundEffect}
       />,
     );
   } else {

src/components/CallFooterViewModel.tsx

@@ -14,6 +14,7 @@ import { type MenuOptions } from "./MediaMuteAndSwitchButton";
 import { type MediaDevices } from "../state/MediaDevices";
 import {
   backgroundBlur as backgroundBlurSettings,
+  backgroundEffect as backgroundEffectSetting,
   debugTileLayout as debugTileLayoutSetting,
 } from "../settings/settings";
 import { type Behavior, constant } from "../state/Behavior";
@@ -76,6 +77,8 @@ function buildDeviceBehaviors(
   | "selectVideoButtonOption$"
   | "toggleBlur$"
   | "videoBlurEnabled$"
+  | "backgroundEffect$"
+  | "selectBackgroundEffect$"
 > {
   const options$ = (
     available$: Behavior<Map<string, MenuOptions["label"]>>,
@@ -128,6 +131,20 @@ function buildDeviceBehaviors(
       ),
     ),
     videoBlurEnabled$: backgroundBlurSettings.value$,
+    backgroundEffect$: backgroundEffectSetting.value$,
+    // Withholding the callback is what renders the section disabled, the same
+    // way the speaker section is disabled where no output can be chosen.
+    selectBackgroundEffect$: scope.behavior(
+      disableSwitcher$.pipe(
+        map((switcherDisabled) =>
+          !switcherDisabled && supportsBackgroundProcessors()
+            ? (id: string): void => {
+                backgroundEffectSetting.setValue(id);
+              }
+            : undefined,
+        ),
+      ),
+    ),
   };
 }