Add full shell, replaceable Omics adapter and bilingual interaction

Implement approved specification #32 and tickets #33-#37. Keep host authentication server-verified and pin session interaction language. Compile scoped base selectors for browser compatibility and retain full gutters during CSS pruning.

frontend/src/widgets/FreetextWidget.test.tsx

@@ -1,6 +1,29 @@
 import { render, screen } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { FreetextWidget } from "./FreetextWidget";
+
+function reloadIsBlocked() {
+  const event = new Event("beforeunload", { cancelable: true });
+  window.dispatchEvent(event);
+  return event.defaultPrevented;
+}
+
+test("protects an answer draft until cleared or unmounted, including after sending", async () => {
+  const onRespond = vi.fn();
+  const { unmount } = render(<FreetextWidget descriptor={{ id: "u1", widget: "freetext" }} onRespond={onRespond} />);
+  expect(reloadIsBlocked()).toBe(false);
+  await userEvent.type(screen.getByRole("textbox"), "Draft answer");
+  expect(reloadIsBlocked()).toBe(true);
+  await userEvent.clear(screen.getByRole("textbox"));
+  expect(reloadIsBlocked()).toBe(false);
+  await userEvent.type(screen.getByRole("textbox"), "Answer{Enter}");
+  expect(onRespond).toHaveBeenCalledWith({ id: "u1", kind: "freetext", text: "Answer" });
+  expect(reloadIsBlocked()).toBe(true);
+  await userEvent.type(screen.getByRole("textbox"), " updated");
+  expect(reloadIsBlocked()).toBe(true);
+  unmount();
+  expect(reloadIsBlocked()).toBe(false);
+});
 test("submits typed text", async () => {
   const onRespond = vi.fn();
   render(<FreetextWidget descriptor={{ id: "u1", widget: "freetext" }} onRespond={onRespond} />);