feat(admin): the AI card shows the day's spend split by who paid

The provider-health route answered a spendToday payload that nothing rendered,
which is the pattern the two-ended rule exists to stop. It is also the screen
the operator opens when a surface refuses on budget, and the one mixed number
could not answer the question that raises: a day at 1.24 million tokens is
alarming until the card says that 151 200 of them were the instance's own key
and the rest ran on the users' own plans. The operator ceiling is enforced
against the second figure. Copy lands in all seven locales.

src/components/admin/__tests__/provider-health-spend-today.test.tsx

@@ -0,0 +1,72 @@
+import { describe, it, expect, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { I18nProvider } from "@/lib/i18n/context";
+
+/**
+ * v1.38.19 (Wave E) — the day's spend, split by who paid for it.
+ *
+ * `/api/admin/provider-health` answers `spendToday` and nothing rendered it,
+ * which is the "the reader is the follow-up" shape the two-ended rule exists to
+ * stop. It is also the one screen that answers the question a budget refusal
+ * raises: a day at 1.24 M tokens is alarming until you can see that 151 200 of
+ * them were the instance's own key and the rest ran on the users' own plans —
+ * and it is the second figure the operator ceiling is enforced against.
+ */
+
+const mockQueryState = vi.hoisted(() => ({
+  data: null as null | object,
+  isPending: false,
+  isError: false,
+}));
+
+vi.mock("@tanstack/react-query", () => ({
+  useQuery: () => ({
+    data: mockQueryState.data,
+    isPending: mockQueryState.isPending,
+    isError: mockQueryState.isError,
+  }),
+}));
+
+import { ProviderHealthSection } from "../provider-health-section";
+
+function render(data: object | null) {
+  mockQueryState.data = data;
+  mockQueryState.isPending = false;
+  mockQueryState.isError = false;
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale="en">
+      <ProviderHealthSection />
+    </I18nProvider>,
+  );
+}
+
+describe("<ProviderHealthSection> — today's spend by cost owner", () => {
+  it("shows both figures and the day they belong to", () => {
+    const html = render({
+      providers: [],
+      spendToday: {
+        dateKey: "2026-09-11",
+        totalTokens: 1_240_000,
+        operatorTokens: 151_200,
+      },
+    });
+    expect(html).toContain("2026-09-11");
+    expect(html).toContain("1,240,000");
+    expect(html).toContain("151,200");
+  });
+
+  it("renders a zero day rather than hiding the readout", () => {
+    const html = render({
+      providers: [],
+      spendToday: { dateKey: "2026-09-11", totalTokens: 0, operatorTokens: 0 },
+    });
+    expect(html).toContain('data-slot="ai-spend-today"');
+  });
+
+  it("says nothing when the payload carries no spend", () => {
+    expect(render({ providers: [] })).not.toContain(
+      'data-slot="ai-spend-today"',
+    );
+  });
+});