feat(filters): make the feed's channel filter reachable

`filters.channelId` was settable by exactly one thing: a "?channel=" URL from a
shared view. The panel still rendered a CHANNEL card whose only control was
"remove" — a remove button for a filter the UI could not apply.

Two ways in now. The panel gets a real Channel group (searchable picker,
first-class alongside date/tags/language, so the chip row surfaces it for free);
normalizeLayout appends it to saved layouts, so nobody loses their arrangement.
And a subscribed channel's page gets "Show in my feed", which applies the filter
and keeps the rest of your filters — the point is "this channel, the way I
normally read", which the channel page itself can't answer (it runs show=all,
scope=all over the whole catalog).

The picker owns its channel query so a few-hundred-entry list loads when the
panel is actually opened, not on every feed visit, and says "showing 50 of N"
rather than quietly stopping.

frontend/src/App.tsx

@@ -843,6 +843,17 @@ export default function App() {
               view={view}
               onBack={closeChannel}
               onOpenChannel={openChannel}
+              onShowInFeed={() => {
+                // Keep the rest of the feed's filters — the point is "this channel, the way I
+                // normally read": unwatched, my tags, my date window.
+                setFilters({
+                  ...filters,
+                  channelId: channelView.id,
+                  channelName: channelView.name,
+                });
+                closeChannel();
+                setPage("feed");
+              }}
             />
           </Suspense>
         ) : (

frontend/src/components/ChannelPage.tsx

@@ -1,7 +1,7 @@
 import { useCallback, useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
-import { ArrowLeft, Ban, Check, ExternalLink, Loader2, Plus, RefreshCw } from "lucide-react";
+import { ArrowLeft, Ban, Check, ExternalLink, Loader2, Plus, RefreshCw, SlidersHorizontal } from "lucide-react";
 import Avatar from "./Avatar";
 import Feed from "./Feed";
 import { useConfirm } from "./ConfirmProvider";
@@ -56,12 +56,17 @@ export default function ChannelPage({
   view,
   onBack,
   onOpenChannel,
+  onShowInFeed,
 }: {
   channelId: string;
   initialName?: string;
   me: Me;
   view: "grid" | "list";
   onBack: () => void;
+  // Narrow the real feed to this channel and go there. Offered only for a channel you're
+  // subscribed to: the feed defaults to scope "my", so filtering it to a channel you don't
+  // follow would just land you on an empty page.
+  onShowInFeed: () => void;
   onOpenChannel: (id: string, name?: string) => void;
 }) {
   const { t, i18n } = useTranslation();
@@ -290,6 +295,16 @@ export default function ChannelPage({
             >
               <ExternalLink className="w-4 h-4" />
             </a>
+            {ch?.subscribed && (
+              <button
+                onClick={onShowInFeed}
+                title={t("channel.showInFeed")}
+                aria-label={t("channel.showInFeed")}
+                className="inline-flex items-center justify-center w-9 h-9 rounded-lg text-muted hover:text-accent border border-border hover:border-accent transition"
+              >
+                <SlidersHorizontal className="w-4 h-4" />
+              </button>
+            )}
             {!me.is_demo && (
               <button
                 onClick={() => block.mutate()}

frontend/src/components/ChannelPicker.tsx

@@ -0,0 +1,87 @@
+import { useState } from "react";
+import { useTranslation } from "react-i18next";
+import { useQuery } from "@tanstack/react-query";
+import { X } from "lucide-react";
+import { api, type FeedFilters } from "../lib/api";
+import { inputCls } from "./ui/form";
+
+const MAX_ROWS = 50;
+
+// Pick one channel to narrow the feed to. Until this existed, `filters.channelId` was settable only
+// via a shared "?channel=" link — the panel had a remove button for a filter nothing could apply.
+//
+// It owns its channel query rather than letting the Sidebar hold it: the Sidebar is mounted for the
+// whole feed page, but SidePanel only renders its children once the panel is open, so keeping the
+// fetch here means a subscription list of a few hundred loads when the picker is actually looked at.
+export default function ChannelPicker({
+  filters,
+  setFilters,
+}: {
+  filters: FeedFilters;
+  setFilters: (f: FeedFilters) => void;
+}) {
+  const { t } = useTranslation();
+  const [query, setQuery] = useState("");
+  const channelsQuery = useQuery({
+    queryKey: ["channels"],
+    queryFn: api.channels,
+    staleTime: 5 * 60_000,
+  });
+
+  if (filters.channelId) {
+    const name =
+      filters.channelName ??
+      channelsQuery.data?.find((c) => c.id === filters.channelId)?.title ??
+      (channelsQuery.isLoading ? t("sidebar.loading") : t("sidebar.thisChannel"));
+    return (
+      <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">{name}</span>
+        <X className="w-4 h-4 shrink-0" />
+      </button>
+    );
+  }
+
+  const q = query.trim().toLowerCase();
+  const all = channelsQuery.data ?? [];
+  const matches = q ? all.filter((c) => (c.title ?? c.id).toLowerCase().includes(q)) : all;
+  const shown = matches.slice(0, MAX_ROWS);
+
+  return (
+    <>
+      <input
+        value={query}
+        onChange={(e) => setQuery(e.target.value)}
+        placeholder={t("sidebar.channelSearch")}
+        aria-label={t("sidebar.channelSearch")}
+        className={inputCls}
+      />
+      <div className="mt-1.5 max-h-44 overflow-y-auto no-scrollbar flex flex-col gap-0.5">
+        {shown.length === 0 ? (
+          <div className="px-2 py-1.5 text-xs text-muted">
+            {channelsQuery.isLoading ? t("sidebar.loading") : t("sidebar.noChannelMatch")}
+          </div>
+        ) : (
+          shown.map((c) => (
+            <button
+              key={c.id}
+              onClick={() => setFilters({ ...filters, channelId: c.id, channelName: c.title ?? undefined })}
+              className="w-full text-left text-sm px-2 py-1.5 rounded-lg text-muted hover:text-fg hover:bg-card truncate transition"
+            >
+              {c.title ?? c.id}
+            </button>
+          ))
+        )}
+      </div>
+      {/* The list is a picker, not a browser — but say so when it's cut off, rather than just
+          stopping and letting a channel look absent. */}
+      {matches.length > shown.length && (
+        <div className="px-2 pt-1.5 text-[11px] text-muted">
+          {t("sidebar.channelMore", { shown: shown.length, total: matches.length })}
+        </div>
+      )}
+    </>
+  );
+}

frontend/src/components/Sidebar.tsx

@@ -1,7 +1,7 @@
 import { type ReactNode, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { keepPreviousData, useQuery } from "@tanstack/react-query";
-import { Library, Pencil, Share2, SlidersHorizontal, User, X } from "lucide-react";
+import { Library, Pencil, Share2, SlidersHorizontal, User } from "lucide-react";
 import { api, type FeedFilters, type Tag } from "../lib/api";
 import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
 import { shareUrl } from "../lib/urlState";
@@ -12,6 +12,7 @@ import TagManager from "./TagManager";
 import SavedViewsWidget from "./SavedViewsWidget";
 import SidePanel from "./SidePanel";
 import PanelGroups, { type PanelItem } from "./PanelGroups";
+import ChannelPicker from "./ChannelPicker";
 
 // Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
 const DATE_PRESETS: { days: number; key: string }[] = [
@@ -101,22 +102,6 @@ export default function Sidebar({
     );
   };
 
-  const needChannelName = !!filters.channelId && !filters.channelName;
-  const channelsQuery = useQuery({
-    queryKey: ["channels"],
-    queryFn: api.channels,
-    enabled: needChannelName,
-    staleTime: 5 * 60_000,
-  });
-  const resolvedChannelName =
-    filters.channelName ??
-    channelsQuery.data?.find((c) => c.id === filters.channelId)?.title ??
-    undefined;
-  const channelChipLabel =
-    resolvedChannelName ??
-    (needChannelName && channelsQuery.isLoading
-      ? t("sidebar.loading")
-      : t("sidebar.thisChannel"));
   const languages = tags.filter((t) => t.category === "language");
   const topics = tags.filter((t) => t.category === "topic");
   const userTags = tags.filter((t) => !t.system);
@@ -154,6 +139,7 @@ export default function Sidebar({
   const available: Record<string, boolean> = {
     savedviews: !isDemo,
     date: true,
+    channel: true,
     language: languages.length > 0,
     topic: topics.length > 0,
     tags: userTags.length > 0,
@@ -163,6 +149,8 @@ export default function Sidebar({
     switch (id) {
       case "savedviews":
         return <SavedViewsWidget filters={filters} onApply={setFilters} />;
+      case "channel":
+        return <ChannelPicker filters={filters} setFilters={setFilters} />;
       case "date":
         return (
           <>
@@ -413,25 +401,6 @@ export default function Sidebar({
         ))}
       </div>
 
-      {filters.channelId && !editing && (
-        <div className="glass-card rounded-xl">
-          <div className="px-3 pt-2 text-xs uppercase tracking-wide text-muted">
-            {t("sidebar.channel")}
-          </div>
-          <div className="px-3 pb-3 pt-2">
-            <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">{channelChipLabel}</span>
-              <X className="w-4 h-4 shrink-0" />
-            </button>
-          </div>
-        </div>
-      )}
-
       <PanelGroups items={items} layout={layout} setLayout={setLayout} editing={editing} />
 
       {tagManagerOpen && (

frontend/src/i18n/locales/en/channel.json

@@ -23,5 +23,6 @@
   "country": "Country",
   "language": "Language",
   "topics": "Topics",
-  "keywords": "Keywords"
+  "keywords": "Keywords",
+  "showInFeed": "Show in my feed"
 }

frontend/src/i18n/locales/en/sidebar.json

@@ -40,7 +40,8 @@
     "content": "Content type",
     "language": "Language",
     "topic": "Topic",
-    "tags": "Your tags"
+    "tags": "Your tags",
+    "channel": "Channel"
   },
   "show": {
     "unwatched": "Unwatched",
@@ -72,5 +73,8 @@
     "1month": "1 month",
     "6months": "6 months",
     "1year": "1 year"
-  }
+  },
+  "channelSearch": "Search channels…",
+  "noChannelMatch": "No channel matches.",
+  "channelMore": "Showing {{shown}} of {{total}} — search to narrow."
 }

frontend/src/i18n/locales/hu/channel.json

@@ -23,5 +23,6 @@
   "country": "Ország",
   "language": "Nyelv",
   "topics": "Témák",
-  "keywords": "Kulcsszavak"
+  "keywords": "Kulcsszavak",
+  "showInFeed": "Mutasd a hírfolyamomban"
 }

frontend/src/i18n/locales/hu/sidebar.json

@@ -40,7 +40,8 @@
     "content": "Tartalomtípus",
     "language": "Nyelv",
     "topic": "Téma",
-    "tags": "Saját címkék"
+    "tags": "Saját címkék",
+    "channel": "Csatorna"
   },
   "show": {
     "unwatched": "Nem nézett",
@@ -72,5 +73,8 @@
     "1month": "1 hónap",
     "6months": "6 hónap",
     "1year": "1 év"
-  }
+  },
+  "channelSearch": "Csatornák keresése…",
+  "noChannelMatch": "Nincs találat.",
+  "channelMore": "{{total}} közül {{shown}} látszik — keress a szűkítéshez."
 }

frontend/src/lib/panelLayout.ts

@@ -16,7 +16,7 @@ export interface PanelLayout {
 // Unknown/stale ids are dropped and any missing (e.g. a group added in a later version) are
 // appended by normalizeLayout, so nothing silently disappears.
 const PANEL_ORDER: Record<PanelId, string[]> = {
-  feed: ["savedviews", "date", "tags", "language", "topic"],
+  feed: ["savedviews", "date", "channel", "tags", "language", "topic"],
   plex: [
     "scope",
     "playlists",