feat: warn on uncertain episode availability

static/episode_availability_warning.ts

@@ -0,0 +1,23 @@
+import { closestFocusable, onReady } from "./utils";
+
+const initEpisodeAvailabilityWarning = (): void => {
+  onReady(() => {
+    const dialog = document.querySelector<HTMLElement>("[data-episode-availability-warning]");
+    const continueButton = document.querySelector<HTMLButtonElement>(
+      "[data-episode-availability-warning-continue]",
+    );
+    if (!dialog || !continueButton) {
+      return;
+    }
+
+    document.body.classList.add("overflow-hidden");
+    closestFocusable(dialog)?.focus();
+
+    continueButton.addEventListener("click", () => {
+      dialog.remove();
+      document.body.classList.remove("overflow-hidden");
+    });
+  });
+};
+
+initEpisodeAvailabilityWarning();