fix(ledger): an order's debt follows its status, as legacy recomputed it (ACC-03)

Legacy never posted order debt; updateRemain recomputed it as
SUM(orders.input) WHERE sts > 4. The port posted it once on entering
DELIVERED_TO_AGENT, guarded on deliveredAt, which:
- posted it twice when an order reached that status again
- posted nothing for an order sent straight to DELIVERED_TO_CUSTOMER
- kept it after a rollback or cancellation

syncOrderDebt compares what the order should owe with the confirmed
ORDER_STOCK entries on it and posts only the difference (append-only,
idempotent). Status removal runs it too, so removing «تحویل به نماینده»
is allowed again, as in legacy. Existing data: 0 orders out of line.

Owner approval: 2026-10-08.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/src/modules/accounting/ledger.service.spec.ts

@@ -0,0 +1,94 @@
+import { LedgerCurrency, LedgerDirection, OrderStatus, Prisma } from '@prisma/client';
+import { LedgerService } from './ledger.service';
+
+/**
+ * ACC-03 / MON-04 — an order's debt follows its status, exactly as legacy's
+ * recomputed `Σ orders.input WHERE sts > 4`: owed once while delivered (to the
+ * expert or the customer), nothing otherwise, never twice.
+ */
+describe('LedgerService.syncOrderDebt', () => {
+  type Entry = { orderId: string; currency: LedgerCurrency; direction: LedgerDirection; amount: Prisma.Decimal; confirmed: boolean };
+
+  function build(order: { status: OrderStatus; totalGoldWeightGrams: string; flatRialCharge: string }) {
+    const entries: Entry[] = [];
+    const balance = { gold: new Prisma.Decimal(0), rial: new Prisma.Decimal(0) };
+    const row = { id: 'o1', customerId: 'c1', ...order };
+    const tx = {
+      order: { findUnique: jest.fn(async () => row) },
+      ledgerEntry: {
+        create: jest.fn(async ({ data }: { data: Entry }) => {
+          entries.push(data);
+          return data;
+        }),
+        groupBy: jest.fn(async ({ where }: { where: { orderId: string; currency: LedgerCurrency } }) => {
+          const out: { direction: LedgerDirection; _sum: { amount: Prisma.Decimal } }[] = [];
+          for (const d of [LedgerDirection.DEBIT, LedgerDirection.CREDIT]) {
+            const hit = entries.filter((e) => e.orderId === where.orderId && e.currency === where.currency && e.direction === d && e.confirmed);
+            if (hit.length) out.push({ direction: d, _sum: { amount: hit.reduce((s, e) => s.add(e.amount), new Prisma.Decimal(0)) } });
+          }
+          return out;
+        }),
+      },
+      customer: {
+        update: jest.fn(async ({ data }: { data: { goldDebtGrams?: { increment: Prisma.Decimal }; fiatDebtRial?: { increment: Prisma.Decimal } } }) => {
+          if (data.goldDebtGrams) balance.gold = balance.gold.add(data.goldDebtGrams.increment);
+          if (data.fiatDebtRial) balance.rial = balance.rial.add(data.fiatDebtRial.increment);
+        }),
+      },
+    };
+    const service = new LedgerService(tx as never);
+    const move = async (status: OrderStatus) => {
+      row.status = status;
+      await service.syncOrderDebt('o1', tx as never);
+    };
+    return { move, entries, balance };
+  }
+
+  it('posts the gold and rial debt once on delivery to the expert', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '10.5', flatRialCharge: '2000' });
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    expect(t.balance.gold.toString()).toBe('10.5');
+    expect(t.balance.rial.toString()).toBe('2000');
+    expect(t.entries).toHaveLength(2);
+  });
+
+  it('never posts twice when the order reaches delivered again (the ACC-03 bug)', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '10.5', flatRialCharge: '0' });
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    await t.move(OrderStatus.DELIVERED_TO_CUSTOMER);
+    expect(t.balance.gold.toString()).toBe('10.5');
+    expect(t.entries).toHaveLength(1);
+  });
+
+  it('takes the debt off when the order goes back, and puts it back once', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '10.5', flatRialCharge: '0' });
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    await t.move(OrderStatus.PREPARING);
+    expect(t.balance.gold.toString()).toBe('0');
+    expect(t.entries[1].direction).toBe(LedgerDirection.CREDIT);
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    expect(t.balance.gold.toString()).toBe('10.5');
+  });
+
+  it('posts the debt when an order goes straight to delivered-to-customer', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '3', flatRialCharge: '0' });
+    await t.move(OrderStatus.DELIVERED_TO_CUSTOMER);
+    expect(t.balance.gold.toString()).toBe('3');
+  });
+
+  it('a cancelled delivered order owes nothing', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '3', flatRialCharge: '500' });
+    await t.move(OrderStatus.DELIVERED_TO_AGENT);
+    await t.move(OrderStatus.CANCELLED);
+    expect(t.balance.gold.toString()).toBe('0');
+    expect(t.balance.rial.toString()).toBe('0');
+  });
+
+  it('posts nothing for an order that was never delivered', async () => {
+    const t = build({ status: OrderStatus.PLACED, totalGoldWeightGrams: '3', flatRialCharge: '500' });
+    await t.move(OrderStatus.ADMIN_APPROVED);
+    await t.move(OrderStatus.PREPARING);
+    expect(t.entries).toHaveLength(0);
+  });
+});