fix(ui): a removed chip's focus outlives its neighbour; a scroll restore yields to the reader

A chip handed its focus to a Clear all or +N that went in the same removal, and the focus fell to
the body. The restore now stops when the reader scrolls, and finishes the way once the Back-to-top
spacer brings the saved spot within reach.

frontend/src/components/ui/Chip.tsx

@@ -3,7 +3,7 @@ import type { ButtonHTMLAttributes, ReactNode } from "react";
 import clsx from "clsx";
 import { X } from "lucide-react";
 import { FocusSafeButton } from "./FocusSafeButton";
-import { focusNeighbour } from "../../lib/useFocusKeeper";
+import { handOffFocus } from "../../lib/useFocusKeeper";
 import { chipClass, type ChipSize, type ChipVariant } from "./chipStyles";
 
 // The chip family (docs/DESIGN.md "One primitive per button family"): a small rounded-full token that
@@ -61,8 +61,8 @@ export const Chip = forwardRef<HTMLButtonElement, ChipProps>(function Chip(
         // went to <body> (round 2, F6 — the active-filter chips of the feed and Plex). Every
         // removal chip gets it here, once, instead of each caller remembering.
         if (removeLabel && e.currentTarget === document.activeElement)
-          focusNeighbour(e.currentTarget);
-        onClick?.(e);
+          handOffFocus(e.currentTarget, () => onClick?.(e));
+        else onClick?.(e);
       }}
       {...rest}
     >
@@ -129,8 +129,8 @@ export function DismissibleChip({
           // next chip (else the previous one, else what follows the row) first, not to <body> (E28
           // review F5). A mouse press on it leaves the focus where it was.
           const chip = e.currentTarget.parentElement;
-          if (chip && e.currentTarget === document.activeElement) focusNeighbour(chip);
-          onDismiss();
+          if (chip && e.currentTarget === document.activeElement) handOffFocus(chip, onDismiss);
+          else onDismiss();
         }}
         aria-label={dismissLabel}
         title={dismissLabel}