feat: platform backbone and field capture, first part (checkpoint)

Platform backbone (plan 2026-10-13-plattform-rueckgrat), reviewed tasks:
- run roles api/worker/job/all with shared startup checks (Task 1)
- schema and migration for DomainEvent, deliveries, JobRun, ThrottlerHit (Task 2)
- audit, notifications and domain events written in the same transaction (Task 3)
- dispatcher with SKIP LOCKED claims, retries and stale release (Task 4)
- worker building blocks: tick, LISTEN/NOTIFY wake-up, health (Task 5)
- worker process and entry points (Task 6)
- throttler counters in Postgres (Task 19)
- separate keys per purpose with key ring (Task 20)
- public origin page without exact location (Task 22)
- shop keys split into read and write (Task 23)
- Kustomize base, components, overlay encry, CI validation (Task 26)

Field capture T3 (plan 2026-10-13-t3-erfassung-am-stand), reviewed tasks:
- brood frames, read endpoints, apiary overview and offline pack
- network basics, offline queue v3, navigation sheets, form building blocks
- new inspection with last-time hints and weather, varroa per day,
  treatment prefill, apiary page with round
- inspection photo (Task 10) is implemented, review pending

Not rolled out. Remaining tasks follow in later commits.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/app/providers.spec.tsx

@@ -0,0 +1,40 @@
+import { useMutation } from "@tanstack/react-query";
+import { act, render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { Providers } from "./providers";
+
+vi.mock("@/lib/auth/auth-context", () => ({
+  AuthProvider: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+}));
+
+function Probe({ mutationFn }: { mutationFn: () => Promise<string> }) {
+  const mutation = useMutation({ mutationFn });
+  return <button onClick={() => mutation.mutate()}>Speichern</button>;
+}
+
+describe("Providers", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    // TanStack's onlineManager tracks the browser events, so restore it too.
+    act(() => {
+      window.dispatchEvent(new Event("online"));
+    });
+  });
+
+  it("runs mutations while navigator.onLine is false", async () => {
+    vi.spyOn(window.navigator, "onLine", "get").mockReturnValue(false);
+    const mutationFn = vi.fn().mockResolvedValue("ok");
+    render(
+      <Providers>
+        <Probe mutationFn={mutationFn} />
+      </Providers>,
+    );
+    // onlineManager (listening once mounted) only learns about airplane mode through the window event.
+    act(() => {
+      window.dispatchEvent(new Event("offline"));
+    });
+    await userEvent.click(screen.getByRole("button", { name: "Speichern" }));
+    await waitFor(() => expect(mutationFn).toHaveBeenCalledTimes(1));
+  });
+});