fix(02-04): set invoice status to SENT on generation

Invoices were created with default DRAFT status, but PaymentService queries
for SENT/PARTIAL/OVERDUE. This broke the generate → pay flow. Now invoices
are immediately SENT with issuedAt timestamp on generation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/__tests__/billing.test.ts

@@ -365,7 +365,7 @@ describe("Invoice generation — POSTPAID", () => {
     const invoice = result!.invoice as Record<string, unknown>;
     expect(Number(invoice.totalAmount)).toBeCloseTo(49.99);
     expect(Number(invoice.subtotal)).toBeCloseTo(49.99);
-    expect(invoice.status).toBe(InvoiceStatus.DRAFT);
+    expect(invoice.status).toBe(InvoiceStatus.SENT);
     expect(invoice.subscriberId).toBe(subscriberId);
   });
 
@@ -615,7 +615,7 @@ describe("Credit auto-application on invoice generation", () => {
     expect(result!.creditApplied).toBe(false);
 
     const invoice = result!.invoice as Record<string, unknown>;
-    expect(invoice.status).toBe(InvoiceStatus.DRAFT);
+    expect(invoice.status).toBe(InvoiceStatus.SENT);
     expect(Number(invoice.amountPaid)).toBe(0);
   });
 
@@ -1000,11 +1000,11 @@ describe("getInvoice and listInvoices", () => {
   });
 
   it("listInvoices filters by status", async () => {
-    const result = await listInvoices(tA(), { status: InvoiceStatus.DRAFT });
-    const allDraft = (result.invoices as Array<Record<string, unknown>>).every(
-      (inv) => inv.status === InvoiceStatus.DRAFT || inv.status === InvoiceStatus.PARTIAL || inv.status === InvoiceStatus.OVERDUE
+    const result = await listInvoices(tA(), { status: InvoiceStatus.SENT });
+    const allSent = (result.invoices as Array<Record<string, unknown>>).every(
+      (inv) => inv.status === InvoiceStatus.SENT || inv.status === InvoiceStatus.PARTIAL || inv.status === InvoiceStatus.OVERDUE
     );
-    // All returned should be DRAFT (some might have been changed to OVERDUE by other tests)
+    // All returned should be SENT (some might have been changed to OVERDUE or PARTIAL by other tests)
     expect(result.invoices).toBeTruthy();
   });
 });

src/lib/services/billing-service.ts

@@ -210,6 +210,8 @@ export async function generateInvoiceForSubscriber(
         subtotal: monthlyPrice,
         totalAmount: monthlyPrice,
         amountPaid: new Prisma.Decimal(0),
+        status: 'SENT',
+        issuedAt: new Date(),
         lines: {
           create: [
             {