feat: feedback round 3 — content-type toggles, channel filter, card polish

- Content type is now three independent toggles (Normal / Shorts / Live·Upcoming);
  the feed is the union of enabled types (backend show_normal + include_shorts +
  include_live)
- Per-channel filter: a button on each card scopes the feed to that channel, shown
  as a removable chip in the sidebar
- Hide now refetches the feed once the change is persisted, so a hidden video shows
  up in the Hidden view immediately (no refresh needed); optimistic updates respect
  the current view
- Grid cards are now distinct panels (card background, border, shadow) that lift on
  hover; clickable channel name in list view too

frontend/src/components/Sidebar.tsx

@@ -1,4 +1,5 @@
 import { useQuery } from "@tanstack/react-query";
+import { X } from "lucide-react";
 import { api, type FeedFilters, type Tag } from "../lib/api";
 
 const SORTS = [
@@ -64,13 +65,27 @@ export default function Sidebar({
 
   const active =
     filters.tags.length > 0 ||
+    !filters.includeNormal ||
     filters.includeShorts ||
     filters.includeLive ||
     filters.show !== "unwatched" ||
-    filters.sort !== "newest";
+    filters.sort !== "newest" ||
+    !!filters.channelId;
 
   return (
     <aside className="w-64 shrink-0 border-r border-border bg-surface/40 overflow-y-auto p-4 space-y-5 hidden md:block">
+      {filters.channelId && (
+        <Section title="Channel">
+          <button
+            onClick={() => setFilters({ ...filters, channelId: undefined, channelName: undefined })}
+            className="w-full flex items-center justify-between gap-2 text-sm px-3 py-2 rounded-lg bg-accent text-accent-fg shadow-sm hover:opacity-90 transition"
+          >
+            <span className="truncate">{filters.channelName ?? "This channel"}</span>
+            <X className="w-4 h-4 shrink-0" />
+          </button>
+        </Section>
+      )}
+
       <Section title="Show">
         <div className="grid grid-cols-2 gap-1.5">
           {SHOWS.map((s) => (
@@ -103,14 +118,19 @@ export default function Sidebar({
         </select>
       </Section>
 
-      <Section title="Content">
+      <Section title="Content type">
         <Toggle
-          label="Include Shorts"
+          label="Normal"
+          checked={filters.includeNormal}
+          onChange={(v) => setFilters({ ...filters, includeNormal: v })}
+        />
+        <Toggle
+          label="Shorts"
           checked={filters.includeShorts}
           onChange={(v) => setFilters({ ...filters, includeShorts: v })}
         />
         <Toggle
-          label="Include live / upcoming"
+          label="Live / Upcoming"
           checked={filters.includeLive}
           onChange={(v) => setFilters({ ...filters, includeLive: v })}
         />
@@ -167,6 +187,7 @@ export default function Sidebar({
               tagMode: "or",
               q: filters.q,
               sort: "newest",
+              includeNormal: true,
               includeShorts: false,
               includeLive: false,
               show: "unwatched",