feat(web): licence banner, settings page and feature gating

web/lib/useLicense.ts

@@ -0,0 +1,21 @@
+"use client";
+
+import { useQuery } from "@tanstack/react-query";
+import { licence, type LicenseInfo } from "@/lib/api";
+
+export function useLicense() {
+    const { data, isLoading } = useQuery<LicenseInfo>({
+        queryKey: ["license"],
+        queryFn: licence.get,
+        staleTime: 60_000,
+    });
+
+    return {
+        license: data,
+        isLoading,
+        isActive: data?.state === "valid",
+        // Features render disabled rather than hidden, so treat "unknown while
+        // loading" as available to avoid a flash of disabled controls.
+        hasFeature: (name: string) => (data ? Boolean(data.features?.[name]) : true),
+    };
+}