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/(app)/layout.spec.tsx

@@ -1,7 +1,8 @@
 import { describe, expect, it, vi } from "vitest";
-import { render, screen } from "@testing-library/react";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
 import { Card, CardContent } from "@/components/ui/card";
 import { StickySubmit } from "@/components/form/sticky-submit";
+import { purgeStaleDraftPhotos } from "@/lib/photos/store";
 import AppLayout from "./layout";
 
 vi.mock("next/navigation", () => ({
@@ -27,8 +28,24 @@ vi.mock("@/lib/auth/auth-context", () => ({
 }));
 
 vi.mock("@/components/notification-bell", () => ({ NotificationBell: () => null }));
-vi.mock("@/components/offline-sync-badge", () => ({ OfflineSyncBadge: () => null }));
+vi.mock("@/components/offline/offline-band", () => ({
+  OfflineBand: ({
+    userId,
+    pageContentRef,
+  }: {
+    userId: string;
+    pageContentRef: { current: HTMLElement | null };
+  }) => (
+    <div data-testid="offline-band">
+      {userId}
+      <button type="button" onClick={() => pageContentRef.current?.focus()}>
+        Fokus auf den Seiteninhalt
+      </button>
+    </div>
+  ),
+}));
 vi.mock("@/components/user-avatar", () => ({ UserAvatar: () => null }));
+vi.mock("@/lib/photos/store", () => ({ purgeStaleDraftPhotos: vi.fn().mockResolvedValue(0) }));
 
 // A box with overflow auto/scroll/hidden is a scroll container. Any such
 // ancestor of the page content captures `position: sticky` (StickySubmit),
@@ -42,6 +59,47 @@ function expectNoScrollContainerAbove(element: HTMLElement) {
 }
 
 describe("AppLayout", () => {
+  it("shows the offline band for the signed-in user right below the header", () => {
+    render(
+      <AppLayout>
+        <p>Seiteninhalt</p>
+      </AppLayout>,
+    );
+
+    const band = screen.getByTestId("offline-band");
+    expect(band).toHaveTextContent("u1");
+    expect(band.previousElementSibling?.tagName).toBe("HEADER");
+  });
+
+  it("gives the band the page content wrapper as a stable focus target", () => {
+    render(
+      <AppLayout>
+        <p>Seiteninhalt</p>
+      </AppLayout>,
+    );
+
+    fireEvent.click(screen.getByRole("button", { name: "Fokus auf den Seiteninhalt" }));
+
+    const wrapper = screen.getByText("Seiteninhalt").closest("[tabindex='-1']");
+    expect(wrapper).not.toBeNull();
+    expect(wrapper).toHaveFocus();
+    expect(wrapper?.previousElementSibling).toBe(screen.getByTestId("offline-band"));
+  });
+
+  it("deletes photos of form drafts older than 3 days when the app starts", async () => {
+    vi.mocked(purgeStaleDraftPhotos).mockClear();
+    const before = Date.now();
+    render(
+      <AppLayout>
+        <p>Seiteninhalt</p>
+      </AppLayout>,
+    );
+
+    await waitFor(() => expect(purgeStaleDraftPhotos).toHaveBeenCalledTimes(1));
+    const [now] = vi.mocked(purgeStaleDraftPhotos).mock.calls[0];
+    expect(now).toBeGreaterThanOrEqual(before);
+  });
+
   it("does not wrap the page content in its own scroll container", () => {
     render(
       <AppLayout>