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/Feed.tsx

@@ -37,6 +37,7 @@ import { type SortOption } from "../lib/columnSort";
 import { FEED_VIEWS, type FeedView } from "../lib/feedView";
 import { clearedFilters, useActiveFilters } from "../lib/useActiveFilters";
 import ActiveFilterChips from "./ActiveFilterChips";
+import SelectedViewChip from "./SelectedViewChip";
 import { LoadingState, StateMessage } from "./QueryState";
 import { PageToolbar } from "./PageShell";
 import { useWizard } from "./WizardProvider";
@@ -677,10 +678,15 @@ export default function Feed({
         <div className={channelScoped ? "px-4 sm:px-6" : "px-4 pt-2 pb-1"}>
           {toolbar}
           {!channelScoped && (
-            <ActiveFilterChips
-              filters={activeFilters}
-              onClearAll={() => setFilters(clearedFilters(filters))}
-            />
+            <div className="flex flex-wrap items-start gap-2">
+              {/* The active personal view (if any) leads the applied-filter row; ActiveFilterChips
+                  brings the row's own bottom padding. */}
+              <SelectedViewChip />
+              <ActiveFilterChips
+                filters={activeFilters}
+                onClearAll={() => setFilters(clearedFilters(filters))}
+              />
+            </div>
           )}
         </div>
       </PageToolbar>