feat(feed): removable active-filter chips above the feed

With the filter panel now collapsed to a tab, there was no way to see what was
narrowing the feed without opening it. Every applied filter is now a chip you
can drop on its own, with a Clear all when more than one is on.

The panel's count badge and the chip row read the SAME list (lib/useActiveFilters),
so they can't disagree about what's applied; that list also owns the reset both
"Clear all"s share. Replaces the hand-summed activeCount in Sidebar.

frontend/src/components/Feed.tsx

@@ -14,6 +14,8 @@ import {
   SORT_KEYS,
   type SortKey,
 } from "../lib/feedSort";
+import { clearedFilters, useActiveFilters } from "../lib/useActiveFilters";
+import ActiveFilterChips from "./ActiveFilterChips";
 import VirtualFeed from "./VirtualFeed";
 // Lazy: the in-app YouTube player (IFrame API) loads only when a video is first opened.
 const PlayerModal = lazy(() => import("./PlayerModal"));
@@ -84,6 +86,8 @@ export default function Feed({
   channelScoped?: boolean;
 }) {
   const { t } = useTranslation();
+  // Same list the panel's badge counts — see lib/useActiveFilters.
+  const activeFilters = useActiveFilters(filters, setFilters);
   const sortKeys = channelScoped
     ? SORT_KEYS.filter((k) => k !== "subscribers" && k !== "priority")
     : SORT_KEYS;
@@ -625,6 +629,7 @@ export default function Feed({
   return (
     <div className="p-4">
       {toolbar}
+      <ActiveFilterChips filters={activeFilters} onClearAll={() => setFilters(clearedFilters(filters))} />
       {items.length === 0 ? (
         <div className="py-16 text-center text-muted">
           <p>{t("feed.noMatches")}</p>