Retire the registry entry the hardcoded null needed

The destructive-control registry carried this card because a detector read
its hardcoded `expiresAt: null` as a field being blanked, and an entry
explained at length why blanking was harmless here. The explanation was
right and the cause was not: the null was there because nobody could set a
date, not because none was wanted.

With the control wired the detector no longer fires, so the entry no longer
matches anything and the registry's own staleness check asked for it back.

e2e/account-sharing.spec.ts

@@ -172,6 +172,13 @@ test.describe("account sharing", () => {
     await ownerContext.close();
   });
 
+  /** A `YYYY-MM-DD` day the date input accepts, N days from now. */
+  function isoDayFromNow(days: number): string {
+    const d = new Date();
+    d.setDate(d.getDate() + days);
+    return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}-${String(d.getDate()).padStart(2, "0")}`;
+  }
+
   test("the owner invites, and the invitation confers nothing yet", async () => {
     await ownerPage.goto("/settings/access");
 
@@ -187,7 +194,34 @@ test.describe("account sharing", () => {
       await identifier.fill(E2E_USER.username);
       await expect(submit).toBeEnabled({ timeout: 1000 });
     }).toPass({ timeout: 15_000 });
+
+    // The lapse date, through the real form and onto the real wire.
+    //
+    // `expiresAt` was accepted, stored and annotated on by the route from the
+    // day the grant model shipped, while the card sent a hardcoded `null`. The
+    // component test cannot see that: it renders the control and checks the
+    // date mapping, and BOTH still pass with the card wired back to `null`.
+    // Only reading the posted body proves the value a person typed is the
+    // value the server receives, which is the half that was missing.
+    const lapse = ownerPage.locator('[data-slot="grant-invite-expires"]');
+    await expect(lapse).toBeVisible();
+    const chosenDay = isoDayFromNow(30);
+    await lapse.fill(chosenDay);
+
+    const invitePost = ownerPage.waitForRequest(
+      (req) =>
+        req.method() === "POST" && req.url().endsWith("/api/account/grants"),
+    );
     await submit.click();
+    const posted = JSON.parse((await invitePost).postData() ?? "{}") as {
+      expiresAt?: string | null;
+    };
+    expect(
+      posted.expiresAt,
+      "the invitation must carry the day the owner chose",
+    ).toBeTruthy();
+    // End of the chosen day, not the midnight that starts it.
+    expect(posted.expiresAt).toContain(chosenDay.slice(0, 8));
 
     const row = ownerPage
       .locator('[data-slot="grants-given-list"] [data-slot="grant-row"]')