fix(feed): no active-filter chips on channel pages

A channel page renders the Feed from its own baseline — channel-scoped,
whole-catalog, show-all, live included — so measuring it against the feed's
defaults labelled all five as "filters you applied" when they are just the page
being itself. It also has no filter sidebar (App hides it), and revealing what
the collapsed panel hides is the chip row's only job.

frontend/src/components/Feed.tsx

@@ -629,7 +629,16 @@ export default function Feed({
   return (
     <div className="p-4">
       {toolbar}
-      <ActiveFilterChips filters={activeFilters} onClearAll={() => setFilters(clearedFilters(filters))} />
+      {/* Channel pages get no chips: they have no filter panel to reveal (App hides the sidebar for
+          them), and their Feed starts from its OWN baseline — channel-scoped, whole-catalog,
+          show-all — so every one of those would render as a "filter you applied" when it's just the
+          page being itself. */}
+      {!channelScoped && (
+        <ActiveFilterChips
+          filters={activeFilters}
+          onClearAll={() => setFilters(clearedFilters(filters))}
+        />
+      )}
       {items.length === 0 ? (
         <div className="py-16 text-center text-muted">
           <p>{t("feed.noMatches")}</p>