email: keepPreviousData so searching doesn't remount the panel and drop input focus

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/apps/officer-web/Screens/Dashboard/Email/EmailList.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useRef, useState } from 'react';
 import { Link } from 'react-router';
-import { useQuery, useQueryClient } from '@tanstack/react-query';
+import { useQuery, useQueryClient, keepPreviousData } from '@tanstack/react-query';
 import { ChevronLeft, ChevronRight, Inbox, Loader2, Mail, Paperclip, RefreshCw, Search, Send, ShieldAlert, Trash2, X } from 'lucide-react';
 import { toast } from 'sonner';
 import { Button } from '@/components/ui/button';
@@ -66,6 +66,9 @@ export const EmailList = () => {
       isSearching
         ? client.get<{ messages: EmailSummary[]; total: number }>(`/email/search?q=${encodeURIComponent(debouncedSearch)}&page=${page}&limit=${LIMIT}`)
         : client.get<{ messages: EmailSummary[]; total: number }>(`/email/messages?page=${page}&limit=${LIMIT}&folder=${folder}`),
+    // Keep the previous results visible while the next query loads, so switching search terms/pages
+    // never bails to the full-panel loading view (which would unmount the search input and drop focus).
+    placeholderData: keepPreviousData,
   });
 
   // Auto-switch to "all" if inbox filter returns nothing but emails exist (not while searching)