feat(feed): flatten the filter rail — dropdown upload-date, non-collapsible widgets, title triggers

Rework the feed filter rail into simpler label + control rows:
- Remove the rail's own "Clear all" (the chip row above the cards already
  surfaces one whenever any filter is active).
- Replace the Upload date chip group with a single-select dropdown
  (DateFilterSelect): an "Any time" clear, more presets (2 weeks / 3 months /
  2 years / 5 years) and a "Custom range" that reveals from/to on select; the
  trigger then reads the chosen range. Selection logic is the pure lib/dateFilter
  (applyDateChip -> selectDateChip, no toggle-off; tests updated).
- Widgets are no longer collapsible: PanelGroup gains `collapsible` (feed passes
  false) so groups render as always-open label + control rows; reorder + hide in
  edit mode stay. Other rails (Plex/Playlists) keep the collapsible islands.
- A non-collapsible group's title can act as its own trigger (PanelItem
  onTitleClick): "Your tags" opens the tag manager, replacing the inline Manage
  button.

frontend/src/components/PanelGroups.tsx

@@ -17,7 +17,16 @@ import {
 import type { PanelLayout } from "../lib/panelLayout";
 import PanelGroup from "./PanelGroup";
 
-export type PanelItem = { id: string; title: string; body: ReactNode };
+export type PanelItem = {
+  id: string;
+  title: string;
+  body: ReactNode;
+  /** When set (and the panel is non-collapsible), the group's title becomes a button firing this —
+   *  e.g. the feed's "Your tags" opens the tag manager. */
+  onTitleClick?: () => void;
+  /** Accessible name / tooltip for the title action (what onTitleClick does). */
+  titleActionLabel?: string;
+};
 
 // Renders a panel's islands in the user's saved order, with drag-to-reorder + hide + per-group
 // collapse driven by `layout` (see lib/panelLayout). `items` holds only the currently AVAILABLE
@@ -29,11 +38,15 @@ export default function PanelGroups({
   layout,
   setLayout,
   editing,
+  collapsible = true,
 }: {
   items: PanelItem[];
   layout: PanelLayout;
   setLayout: (l: PanelLayout) => void;
   editing: boolean;
+  /** When false, groups render as plain (always-open) label + control rows — no collapse chevron.
+   *  Reorder + hide (in edit mode) stay. Default true (the collapsible-island look). */
+  collapsible?: boolean;
 }) {
   const sensors = useSensors(
     useSensor(PointerSensor, { activationConstraint: { distance: 4 } }),
@@ -76,10 +89,13 @@ export default function PanelGroups({
               id={id}
               title={byId.get(id)!.title}
               editing={editing}
+              collapsible={collapsible}
               collapsed={!!layout.collapsed[id]}
               hidden={!!layout.hidden[id]}
               onToggleCollapse={() => toggleCollapse(id)}
               onToggleHidden={() => toggleHidden(id)}
+              onTitleClick={byId.get(id)!.onTitleClick}
+              titleActionLabel={byId.get(id)!.titleActionLabel}
             >
               {byId.get(id)!.body}
             </PanelGroup>