chore: drop duplicate selected count + Discard button from TopBar

Both were redundant:
- "N selected" is already shown by the contextual KeyboardHints pill
  below the FilterBar
- The Discard action is in the RightSidebar Flag section and bound
  to X (and exists as a per-photo button on the thumbnail when
  is_discarded)

Also removes the no-longer-used discardPhotosMutation, the photos
api import, the toast import, the useMutation/useQueryClient imports,
and the usePhotoStore selectedPhotos read — TopBar is leaner now.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/layout/TopBar.tsx

@@ -8,16 +8,11 @@ import {
   Upload,
   Settings,
   Menu,
-  Trash2,
   X,
   ShoppingBasket,
 } from 'lucide-react'
 import clsx from 'clsx'
-import { usePhotoStore } from '../../store/photoStore'
 import { useFilterStore, hasActiveFilters } from '../../store/filterStore'
-import { photos } from '../../services/api'
-import { toast } from '../ToastContainer'
-import { useMutation, useQueryClient } from '@tanstack/react-query'
 import { useHeapsQuery } from '../../hooks/useHeapsQuery'
 import muliLogo from '../../assets/muli-logo.png'
 
@@ -55,31 +50,12 @@ export function TopBar() {
   }, [searchQuery, storeQ, setStoreQ])
 
   const [viewMode, setViewMode] = useState<'grid' | 'list'>('grid')
-  const selectedPhotos = usePhotoStore((state) => state.selectedPhotos)
-  const clearSelection = usePhotoStore((state) => state.clearSelection)
-  const selectedCount = selectedPhotos.length
-  const queryClient = useQueryClient()
 
-  // Currently active heap (for the T shortcut). Shown as a pill so the user
-  // always knows where their next T-press will land.
+  // Currently active heap. Shown as a pill so the user always knows where
+  // their next P-press will land.
   const { data: heapsList = [] } = useHeapsQuery()
   const activeHeap = heapsList.find((h) => h.is_active)
-  
-  // Mutation for discarding selected photos
-  const discardPhotosMutation = useMutation({
-    mutationFn: async () => {
-      await photos.bulkUpdate(selectedPhotos, { discard: true })
-    },
-    onSuccess: () => {
-      toast.success('Discarded', `${selectedCount} photo${selectedCount > 1 ? 's' : ''} discarded`)
-      clearSelection()
-      queryClient.invalidateQueries({ queryKey: ['photos'] })
-    },
-    onError: (error: any) => {
-      toast.error('Failed to discard', error.message || 'An error occurred')
-    },
-  })
-  
+
   return (
     <header className="flex h-12 items-center justify-between border-b border-border bg-surface px-4">
       {/* Left Section - Menu and App Name */}
@@ -100,28 +76,12 @@ export function TopBar() {
         {activeHeap && (
           <span
             className="flex items-center gap-1 rounded bg-primary/20 px-2 py-0.5 text-xs text-primary"
-            title="Active heap — press T to add the selected photos here"
+            title="Active heap — press P to add selected photos here"
           >
             <ShoppingBasket className="h-3 w-3" />
             {activeHeap.name}
           </span>
         )}
-        {selectedCount > 0 && (
-          <>
-            <span className="rounded bg-primary/20 px-2 py-0.5 text-sm text-primary">
-              {selectedCount} selected
-            </span>
-            <button
-              onClick={() => discardPhotosMutation.mutate()}
-              disabled={discardPhotosMutation.isPending}
-              className="flex items-center gap-1 rounded bg-reject/20 px-2 py-0.5 text-sm text-reject hover:bg-reject/30 disabled:opacity-50"
-              title="Discard"
-            >
-              <Trash2 className="h-3.5 w-3.5" />
-              Discard
-            </button>
-          </>
-        )}
       </div>
       
       {/* Center Section - Search */}