fix(plex,channels): address R13 S2 review findings

- Shared usePlexClearFilters hook replaces the duplicated clearAll (was copied in
  PlexBrowse and PlexSidebar) — one "reset every Plex narrowing" both call.
- The Plex duration chip's minutes unit is localized (plex.filter.durationUnit:
  "min"/"perc") instead of a hardcoded "m".
- The Plex collection chip falls back to the "Collection" label, not the raw
  rating_key id, when collectionTitle is missing.
- Dropped the dead rowClassName that dimmed hidden rows in the subscribed table
  (hidden channels are excluded there now — they live in the Hidden tab).
- Renamed the misleading `set` null-check predicate to `has`.

Gate green: tsc/eslint-0/prettier/knip clean, vitest 106.

frontend/src/components/PlexSidebar.tsx

@@ -3,7 +3,7 @@ import { qk } from "../lib/queryKeys";
 import { useTranslation } from "react-i18next";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { Layers, ListMusic, Plus, SlidersHorizontal, X } from "lucide-react";
-import { api, EMPTY_PLEX_FILTERS, plexFilterCount, type PlexFilters } from "../lib/api";
+import { api, plexFilterCount, type PlexFilters } from "../lib/api";
 import { healPlexSort, plexSortOptions, PLEX_SORT_FALLBACK } from "../lib/plexSort";
 import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
 import { useDebounced } from "../lib/useDebounced";
@@ -11,6 +11,7 @@ import { useScrollFade } from "../lib/useScrollFade";
 import SidePanel from "./SidePanel";
 import PanelGroups, { type PanelItem } from "./PanelGroups";
 import SortControl from "./SortControl";
+import { usePlexClearFilters } from "./usePlexActiveFilters";
 import { usePlex, usePlexActions } from "./PlexProvider";
 
 // The Plex module's left filter column — now the shared floating SidePanel with its filter groups
@@ -123,11 +124,7 @@ export default function PlexSidebar({ layout, setLayout, collapsed, onToggleColl
   const patch = (p: Partial<PlexFilters>) => setFilters({ ...filters, ...p });
   const toggleIn = (arr: string[], v: string) =>
     arr.includes(v) ? arr.filter((x) => x !== v) : [...arr, v];
-  const clearAll = () => {
-    setFilters(EMPTY_PLEX_FILTERS);
-    setShow("all");
-    setSort(PLEX_SORT_FALLBACK);
-  };
+  const clearAll = usePlexClearFilters();
 
   const sortOptions = plexSortOptions(scope, (k) => t(`plex.sort.${k}`));
   const durBucketKey = DURATION_BUCKETS.find(