feat(feed): saved views as a header popover + Personal Views modal + a view chip

Retire the standalone 'Saved views' sidebar panel. The saved-views feature now
lives in three lighter surfaces, coordinated by a new SavedViewsProvider (query +
CRUD + the active/sticky view + modal state):

- the filter panel's header ICON opens a quick-pick popover (apply a view, active
  one checked, plus 'Manage views…');
- the header TITLE ('Filters') opens a new Personal Views modal — a master/detail
  manager: left = the reorderable list + a save-current-filters input, right = the
  selected view's name, its captured filters (shown as the same chips the toolbar
  row uses), default toggle, apply, and delete;
- a SelectedViewChip leads the applied-filter row, naming the active view with a
  warn-coloured 'modified' dot once the live filters diverge from it; clicking it
  reopens the picker.

SidePanel/FilterRail gain optional iconExpanded + onTitleClick slots (feed-only,
hidden for the demo account); the collapsed tab keeps its plain pin behaviour.
SavedViewsWidget is deleted and dropped from the panel layout.

Verified live: icon popover lists HH + Manage; applying HH surfaces the chip and
switches scope; removing a filter lights the dirty dot; the title opens the
master/detail modal with the captured-filters summary. 374 vitest, tsc, eslint
(0 err).

frontend/src/components/Sidebar.tsx

@@ -9,7 +9,9 @@ import { useDebounced } from "../lib/useDebounced";
 import { clearedFilters, useActiveFilters } from "../lib/useActiveFilters";
 import { applyDateChip, deriveDateKey } from "../lib/dateFilter";
 import TagManager from "./TagManager";
-import SavedViewsWidget from "./SavedViewsWidget";
+import SavedViewsPopover from "./SavedViewsPopover";
+import PersonalViewsModal from "./PersonalViewsModal";
+import { useSavedViews } from "./SavedViewsProvider";
 import FilterRail from "./FilterRail";
 import { type PanelItem } from "./PanelGroups";
 import { type MediaSourceKind } from "../lib/mediaSource";
@@ -42,6 +44,7 @@ export default function Sidebar({
 }) {
   const { t } = useTranslation();
   const isDemo = useMe().is_demo;
+  const { modalOpen, openModal } = useSavedViews();
   const filters = useFeedFilters();
   const { setFilters } = useFeedFiltersActions();
   // "Focus this channel in the manager" (from the tag manager here) lives in ChannelsProvider.
@@ -111,7 +114,6 @@ export default function Sidebar({
   }
 
   const available: Record<string, boolean> = {
-    savedviews: !isDemo,
     date: true,
     channel: true,
     language: languages.length > 0,
@@ -121,8 +123,6 @@ export default function Sidebar({
 
   function widgetBody(id: string): ReactNode {
     switch (id) {
-      case "savedviews":
-        return <SavedViewsWidget filters={filters} onApply={setFilters} />;
       case "channel":
         return <ChannelPicker filters={filters} setFilters={setFilters} />;
       case "date": {
@@ -278,10 +278,19 @@ export default function Sidebar({
       setLayout={setLayout}
       items={items}
       actions={actions}
+      // Saved ("personal") views: the header icon opens a quick-pick popover, the title opens the
+      // full manager modal. Hidden for the demo account (no per-user views). Feed rail only.
+      iconExpanded={
+        !isDemo && source === "feed" ? (
+          <SavedViewsPopover trigger={<SlidersHorizontal className="w-4 h-4" />} />
+        ) : undefined
+      }
+      onTitleClick={!isDemo && source === "feed" ? openModal : undefined}
     >
       {tagManagerOpen && (
         <TagManager onClose={() => setTagManagerOpen(false)} onFocusChannel={onFocusChannel} />
       )}
+      {modalOpen && source === "feed" && <PersonalViewsModal />}
     </FilterRail>
   );
 }