fix(sync): add Sachbearbeiter to dienstgrad constraint; add catalog browser dialog for external order position

frontend/src/pages/Mitglieder.tsx

@@ -91,7 +91,7 @@ function Mitglieder() {
   const [selectedStatus, setSelectedStatus] = useState<StatusEnum[]>([]);
   const [selectedDienstgrad, setSelectedDienstgrad] = useState<DienstgradEnum[]>([]);
   const [page, setPage] = useState(0);       // MUI uses 0-based
-  const pageSize = 25;
+  const [pageSize, setPageSize] = useState(25);
 
   // Track previous debounced search to reset page
   const prevSearch = useRef(debouncedSearch);
@@ -108,7 +108,7 @@ function Mitglieder() {
         status: selectedStatus.length > 0 ? selectedStatus : undefined,
         dienstgrad: selectedDienstgrad.length > 0 ? selectedDienstgrad : undefined,
         page: page + 1,  // convert to 1-based for API
-        pageSize,
+        pageSize: pageSize === -1 ? 0 : pageSize,  // -1 = MUI "Alle" sentinel → 0 = backend "no limit"
       });
       setMembers(items);
       setTotal(t);
@@ -336,7 +336,12 @@ function Mitglieder() {
             page={page}
             onPageChange={(_e, newPage) => setPage(newPage)}
             rowsPerPage={pageSize}
-            rowsPerPageOptions={[pageSize]}
+            rowsPerPageOptions={[25, 50, 100, { value: -1, label: 'Alle' }]}
+            onRowsPerPageChange={(e) => {
+              setPageSize(parseInt(e.target.value, 10));
+              setPage(0);
+            }}
+            labelRowsPerPage="Einträge pro Seite:"
             labelDisplayedRows={({ from, to, count }) =>
               `${from}–${to} von ${count !== -1 ? count : `mehr als ${to}`}`
             }