Add a background without putting it on

- Whether choosing a file should also wear it is still open, so this does
  the smaller thing: the image joins the others and the user says when
- Reverts the auto-selection added earlier, which was never proven: the
  stories carry selection as a fixed arg, so nothing there could show it

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

src/components/CallFooter.tsx

@@ -214,14 +214,11 @@ export const CallFooter: FC<FooterProps> = ({
 
   const onAddBackgroundImage = useCallback(
     (file: File): void => {
-      // Chosen for the user straight away: they picked this picture to use it,
+      // Added, not chosen. Whether picking a file should also put it on is
-      // and leaving it unselected would ask them to pick it twice.
+      // still open, so this does the smaller thing: the image appears among
+      // the others and the user says when to wear it.
       setBackgroundEffectError(undefined);
-      addBackground(file)
+      addBackground(file).catch((e) => {
-        .then((id) =>
-          selectBackgroundEffect?.(serializeEffect({ kind: "added", id })),
-        )
-        .catch((e) => {
         // TODO: FR-021 wants the user told what went wrong. There is no
         // surface for that in the menu yet, and inventing one is design's
         // call, so for now this is only logged.
@@ -234,7 +231,7 @@ export const CallFooter: FC<FooterProps> = ({
         );
       });
     },
-    [addBackground, selectBackgroundEffect, whyRefused],
+    [addBackground, whyRefused],
   );
 
   // The catalogue is named here rather than in the view model: the names are