routes: keep paging when client-side region filtering starves the table

A multi-IATA region filters globally-paged rows client-side, and scroll
was the only trigger for the next page — an empty or too-short filtered
list could never fire it, so routes deeper in the cursor stream were
unreachable ('No routes' with routes that exist). Pull pages until the
region has a screenful or the cap calls it sparse.

src/features/routes/RouteTable.tsx

@@ -169,7 +169,7 @@ export function RouteTable() {
 
   // Page the route set on demand (50 at a time, cursor = last route's lastSeen ms) — the DataTable
   // pulls the next page via loadMore() as you scroll, instead of eagerly loading the whole set.
-  const { items: listRoutes, loadedCount, isPaging, isError, isLoading: listLoading, loadMore } =
+  const { items: listRoutes, loadedCount, isPaging, isError, isLoading: listLoading, loadMore, hasMore } =
     useInfinitePages<KnownRoute>({
       queryKey: ["routes", serverIata ?? ""],
       queryFn: (cursor) => getKnownRoutesPage({ iata: serverIata, cursor }),
@@ -223,6 +223,16 @@ export function RouteTable() {
     [rows, selectedKey],
   );
 
+  // A multi-IATA region filters globally-paged rows client-side, so the filtered list can be too
+  // short to ever trigger scroll paging — or empty, with the region's routes deeper in the cursor
+  // stream. Keep pulling pages until there's a screenful or the cap says the region is just sparse.
+  useEffect(() => {
+    if (search || serverIata || !iatas?.length) return;
+    if (!hasMore || isPaging) return;
+    if ((rows?.length ?? 0) >= 50 || loadedCount >= 1000) return;
+    loadMore();
+  }, [search, serverIata, iatas, hasMore, isPaging, rows, loadedCount, loadMore]);
+
   const canSearch = !!(from.trim() && to.trim() && searchIatas.length >= 1);
   // clear any selection when the visible list changes out from under it (search submit/clear)
   const submitSearch = useCallback(() => {

tests/features/routes/RouteTable.test.tsx

@@ -30,11 +30,11 @@ const mockGetRegions = vi.mocked(getRegions);
 
 const node = (id: string, name: string) => ({ id, name, publicKey: "deadbeef" });
 
-function renderTable() {
+function renderTable(selection = ALL_REGIONS) {
   const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
   const wrapper = ({ children }: { children: ReactNode }) => (
     <QueryClientProvider client={client}>
-      <RegionProvider defaultSelection={ALL_REGIONS}>{children}</RegionProvider>
+      <RegionProvider defaultSelection={selection}>{children}</RegionProvider>
     </QueryClientProvider>
   );
   render(<RouteTable />, { wrapper });
@@ -103,6 +103,25 @@ describe("RouteTable search", () => {
     expect(screen.getByText("Dst Node")).toBeInTheDocument();
   });
 
+  it("keeps paging for a multi-IATA region until its routes surface", async () => {
+    const foreign: KnownRoute = { id: 1, iata: "CCC", hopCount: 1, hops: [], firstSeen: 1, lastSeen: 5, observationCount: 9 };
+    const wanted: KnownRoute = { id: 2, iata: "AAA", hopCount: 2, hops: [], firstSeen: 1, lastSeen: 3, observationCount: 17 };
+    // first global page has nothing from the region; the region's route sits on page two
+    mockGetKnownRoutesPage.mockImplementation(({ cursor } = {}) =>
+      Promise.resolve(
+        cursor === undefined
+          ? { items: [foreign], nextCursor: 5, hasMore: true }
+          : { items: [wanted], nextCursor: null, hasMore: false },
+      ),
+    );
+
+    renderTable({ regions: [], iatas: ["AAA", "BBB"] });
+
+    // without fill-paging the table dead-ends on "No routes" — scroll can never fire on an empty list
+    expect(await screen.findByText("17")).toBeInTheDocument();
+    expect(mockGetKnownRoutesPage.mock.calls.length).toBeGreaterThanOrEqual(2);
+  });
+
   it("shows a route's observation count in the list", async () => {
     const route: KnownRoute = {
       id: 7,