Persist capture data per session (field values, schema, links)

Capture mode state lived only in React memory and was lost when
reopening a session or remounting EngineProvider.

- Add per-session localStorage capture snapshot (schema, values, links)
- Restore on session mount; persist on field/schema/link changes
- Seed binder links from storage without spurious bus events
- Clean up capture key when session is deleted
- Integration test for reload persistence

tests/integration/capture-session-persist.dom.test.tsx

@@ -0,0 +1,109 @@
+/**
+ * Capture state survives switching away from and back to a session.
+ */
+
+// @vitest-environment happy-dom
+
+import { cleanup, render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import type { Selector } from "@shared/selector";
+
+import type { PdfSelectionCapture } from "@anchor/index";
+import manifest from "../../fixtures/pdfs/manifest.json" with { type: "json" };
+
+import { captureStateKey, loadCaptureState } from "@app/forms/capture-persistence";
+
+interface ViewerProps {
+  pdfUrl: string;
+  storedAnnotations: readonly { id: string; text: string; selectors: readonly Selector[] }[];
+  onSelectionCaptured(capture: PdfSelectionCapture, selectors: Selector[]): void;
+}
+
+vi.mock("@anchor/index", async (importOriginal) => {
+  const original = await importOriginal<typeof import("@anchor/index")>();
+  const MockPdfSpikeViewer = (_props: ViewerProps) => (
+    <div data-testid="mock-pdf-viewer" />
+  );
+  return { ...original, PdfSpikeViewer: MockPdfSpikeViewer };
+});
+
+const FIXTURE = manifest.fixtures.find((f) => f.id === "fristsetzung-bezifferung")!;
+const SYNTHETIC_CANONICAL = ["Pre.", FIXTURE.known_good_quote, "Post."].join(" ");
+const SESSION_NAME = "capture-persist-session";
+
+import { seedSessionWithDoc } from "./helpers/seed-session";
+
+async function loadApp() {
+  const { App } = await import("@app/App");
+  return render(<App />);
+}
+
+describe("Capture session persistence", () => {
+  beforeEach(() => {
+    globalThis.localStorage?.clear();
+    if (typeof window !== "undefined") {
+      history.replaceState(null, "", window.location.pathname);
+    }
+    seedSessionWithDoc({
+      sessionName: SESSION_NAME,
+      documentTitle: FIXTURE.filename,
+      canonicalText: SYNTHETIC_CANONICAL,
+      mode: "forms",
+    });
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+    cleanup();
+  });
+
+  it(
+    "restores typed field values after leaving and reopening the session",
+    { timeout: 20000 },
+    async () => {
+      const user = userEvent.setup();
+      const first = await loadApp();
+
+      const summary = screen.getByLabelText("Summary of the matter");
+      await user.type(summary, "Persisted summary text");
+      await user.click(screen.getByLabelText("Disputed amount"));
+
+      await waitFor(() => {
+        const stored = Object.values(globalThis.localStorage ?? {}).join("");
+        expect(stored).toContain("Persisted summary text");
+      });
+
+      first.unmount();
+
+      await loadApp();
+
+      const restored = screen.getByLabelText("Summary of the matter") as HTMLTextAreaElement;
+      await waitFor(() => {
+        expect(restored.value).toBe("Persisted summary text");
+      });
+    },
+  );
+
+  it(
+    "writes capture state under the per-session storage key",
+    { timeout: 15000 },
+    async () => {
+      const user = userEvent.setup();
+      await loadApp();
+
+      await user.type(screen.getByLabelText("Disputed amount"), "EUR 500");
+
+      await waitFor(() => {
+        const keys = Object.keys(globalThis.localStorage ?? {});
+        const captureKey = keys.find((k) => k.includes(":capture-state:v1"));
+        expect(captureKey).toBeTruthy();
+        const sessionId = captureKey!.split(":")[2];
+        const state = loadCaptureState(sessionId as never);
+        expect(state?.fieldValues.amount).toBe("EUR 500");
+        expect(captureStateKey(sessionId as never)).toBe(captureKey);
+      });
+    },
+  );
+});