fix: usage week aligns with UTC calendar week (#875)

src/app/actions/usage.test.ts

@@ -91,6 +91,34 @@ describe('getUsage', () => {
     });
   });
 
+  it('uses the current UTC calendar week (Monday 00:00) as the week window', async () => {
+    mocks.mockGetUser.mockResolvedValue({ data: { user: { id: 'user-1' } }, error: null });
+    mocks.mockRateLimit.mockResolvedValue({ ok: true });
+
+    const logChain = makeChain();
+    logChain.limit = vi.fn().mockResolvedValue({ data: [], error: null });
+
+    const todayChain = makeChain();
+    todayChain.gte = vi.fn().mockResolvedValue({ data: [], error: null });
+
+    const weekChain = makeChain();
+    const weekGte = vi.fn().mockResolvedValue({ data: [], error: null });
+    weekChain.gte = weekGte;
+
+    mocks.mockServiceFrom
+      .mockReturnValueOnce(logChain)
+      .mockReturnValueOnce(todayChain)
+      .mockReturnValueOnce(weekChain);
+
+    await getUsage();
+
+    const weekBoundary = weekGte.mock.calls[0]?.[1] as string;
+    const boundary = new Date(weekBoundary);
+    expect(boundary.getUTCDay()).toBe(1); // Monday (UTC)
+    expect(weekBoundary).toMatch(/T00:00:00.000Z$/); // start of a calendar day
+    expect(boundary.getTime()).toBeLessThanOrEqual(Date.now());
+  });
+
   it('respects limit parameter', async () => {
     mocks.mockGetUser.mockResolvedValue({ data: { user: { id: 'user-1' } }, error: null });
     mocks.mockRateLimit.mockResolvedValue({ ok: true });

src/app/actions/usage.ts

@@ -41,8 +41,16 @@ export async function getUsage(limit = 100): Promise<UsageSummary> {
   const service = getServiceSupabase();
   if (!service) return empty;
 
-  const dayStart = new Date(new Date().toISOString().slice(0, 10) + 'T00:00:00Z').toISOString();
-  const weekStart = new Date(Date.now() - 7 * 24 * 3600 * 1000).toISOString();
+  // Calendar-aligned windows. dayStart = today 00:00 UTC; weekStart = the
+  // current UTC calendar week's Monday 00:00 (same date_trunc('week')
+  // boundaries the maintainer analytics use), so the week total is stable
+  // within a day and comparable to the weekly chart.
+  const now = new Date();
+  const dayStart = new Date(now.toISOString().slice(0, 10) + 'T00:00:00Z').toISOString();
+  const daysSinceMonday = (now.getUTCDay() + 6) % 7; // 0 = Sunday
+  const weekStart = new Date(
+    Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate() - daysSinceMonday),
+  ).toISOString();
 
   const [logRes, todayRes, weekRes] = await Promise.all([
     service