feat(PROJ-53): Konfigurierbare Listenanzahl pro Seite

- users.list_page_size (Default 25), PATCH /api/auth/preferences,
  Whitelist 25/50/100/200, Wert in login/me-Response
- Settings-UI mit Select, /search nutzt gespeicherte Seitengröße
- /api/search page_size serverseitig auf max. 500 gecappt

fix(PROJ-46): login_attempts-Migration nutzte s.db statt s.pool
(Backend kompilierte nicht)

feat(PROJ-50): DSGVO-Löschersuchen Backend (dsgvo_requests, Handler,
cc_addr/bcc_addr Indexerweiterung) — noch nicht QA'd/deployed

src/app/search/page.tsx

@@ -44,7 +44,7 @@ import { Label } from "@/components/ui/label";
 import { Switch } from "@/components/ui/switch";
 import { Bookmark, BookmarkPlus, Trash2 } from "lucide-react";
 
-const PAGE_SIZE = 25;
+const DEFAULT_PAGE_SIZE = 25;
 
 function formatBytes(bytes: number): string {
   if (bytes < 1024) return `${bytes} B`;
@@ -86,6 +86,8 @@ export default function SearchPage() {
   const { user, loading: authLoading } = useAuth();
   const router = useRouter();
 
+  const pageSize = user?.list_page_size ?? DEFAULT_PAGE_SIZE;
+
   const [query, setQuery] = useState("");
   const [fromFilter, setFromFilter] = useState("");
   const [toFilter, setToFilter] = useState("");
@@ -143,7 +145,7 @@ export default function SearchPage() {
           sort: sort !== "date_desc" ? sort : undefined,
           has_attachment: hasAttachment,
           page: p,
-          page_size: PAGE_SIZE,
+          page_size: pageSize,
         });
         setResults(res.hits || []);
         setTotal(res.total);
@@ -156,7 +158,7 @@ export default function SearchPage() {
         setSearching(false);
       }
     },
-    [query, fromFilter, toFilter, dateFrom, dateTo, sort, hasAttachment]
+    [query, fromFilter, toFilter, dateFrom, dateTo, sort, hasAttachment, pageSize]
   );
 
   // Superadmin has no mail access — redirect to admin dashboard
@@ -170,7 +172,7 @@ export default function SearchPage() {
   useEffect(() => {
     if (!user || user.role === "superadmin") return;
     setSearching(true);
-    searchEmails({ page: 1, page_size: PAGE_SIZE })
+    searchEmails({ page: 1, page_size: pageSize })
       .then((res) => {
         setResults(res.hits || []);
         setTotal(res.total);
@@ -182,7 +184,7 @@ export default function SearchPage() {
         setTotal(0);
       })
       .finally(() => setSearching(false));
-  }, [user]);
+  }, [user, pageSize]);
 
   function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
@@ -339,7 +341,7 @@ export default function SearchPage() {
         date_to: s.query.date_to || undefined,
         has_attachment: s.query.has_attachment === "true" ? true : undefined,
         page: 1,
-        page_size: PAGE_SIZE,
+        page_size: pageSize,
       })
         .then((res) => {
           setResults(res.hits || []);
@@ -364,7 +366,7 @@ export default function SearchPage() {
     }
   }
 
-  const totalPages = Math.ceil(total / PAGE_SIZE);
+  const totalPages = Math.ceil(total / pageSize);
   const allSelected = results.length > 0 && results.every((h) => selected.has(h.id));
 
   return (