fix(invoices): make the Swish QR encode the amount to pay after ROT/RUT deduction (#1685)

* fix(invoices): make the Swish QR encode the amount to pay after ROT/RUT deduction

The Swish payment QR on invoice PDFs encoded the pre-deduction invoice
total (getDisplayTotal), while the totals block and the invoice email
state "Att betala" as total minus the ROT/RUT deduction (getAmountToPay,
fakturamodellen). Since the Swish payload locks the amount (editmask 0),
a customer scanning a RUT/ROT invoice was asked to pay the full total
with no way to correct it: overpaying by the entire skattereduktion.

Swap the QR amount source to getAmountToPay(...).toPay so the QR, the
printed "Att betala" and the email always agree. A fully deducted
invoice (toPay = 0) now renders no QR via the existing amount > 0 guard.
All seven render surfaces (send, preview, pdf, v1 send/pdf, MCP commit,
recurring, issue-and-book) go through this one helper.

Reported by a user: "QR-koden for swish stammer INTE med beloppet man
ska betala. Den tar INTE hansyn till reduktionen."

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(invoices): select the amount-to-pay columns on the v1 pdf and send surfaces

Skeptic review of the Swish QR fix found it was a silent no-op on the v1
GET pdf route: its column projection predated ROT/RUT and omitted
deduction_total (and ore_rounding), so getAmountToPay saw undefined,
treated it as "no deduction", and the route kept emitting a locked
full-amount QR while the sent email said the deducted "Att betala".
INVOICE_FULL_COLUMNS (v1 send renders from it) likewise omitted
ore_rounding, ignoring the per-invoice oresavrundning override there.

Move INVOICE_PDF_COLUMNS into lib/api/v1/invoice-columns.ts, add
deduction_total, deduction_personnummer_last4 and ore_rounding to it, add
ore_rounding to INVOICE_FULL_COLUMNS, and pin the amount-path columns of
both projections with a test: a projection gap does not error, it renders
the wrong money on one surface only, so it must be caught structurally.

Also records the defect and remediation in DECISIONS.md per the
compliance-swarm change-risk finding (the repo has no risk_register.csv;
the decision log is its equivalent).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(invoices): gate the Swish QR to payable documents and restore delivery_date on the v1 pdf

Swedish accounting review round 2: buildSwishQrDataUrl had no non-payable
gate, so a kreditfaktura (a refund document) still produced a locked
Swish payment QR at helper level; the template happens to hide the
payment box for credit notes, but a payment request against a refund
must stay impossible rather than merely unrendered. Apply the same
document gate buildPaymentLinkQrDataUrl already has (invoice documents
without credited_invoice_id only) and pin it with tests replacing the
credit-note parity case.

Also add delivery_date to INVOICE_PDF_COLUMNS: ML 17 kap 24 p.7 requires
leveransdatum on the invoice when it differs from the invoice date, the
template renders exactly that, and the v1 pdf projection silently
dropped it. Same projection-starvation class as the previous commit.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* docs(invoices): name the covered render surfaces and drop the contested lagrum point number

CodeRabbit round 3, both documentation-only: the DECISIONS defect record
said "all surfaces" while the editor preview is deferred to #1686, so it
now lists the covered surfaces explicitly; and the delivery_date comment
cited ML 17 kap 24 p.7 where CodeRabbit reads p.8 in SFS 2023:200 while
the repo's swedish-invoice-compliance reference table says p.7, so the
citation drops the point number and stays at the paragraph, which is
correct under either enumeration. No behavior change.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

lib/invoices/__tests__/pdf-render-helpers.test.ts

@@ -11,11 +11,12 @@
  * mock `fetch` and exercise the real sharp pipeline.
  */
 
-import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi, type MockInstance } from 'vitest'
 import { readFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import sharp from 'sharp'
-import { prepareInvoicePdfRender, buildPaymentLinkQrDataUrl } from '@/lib/invoices/pdf-render-helpers'
+import QRCode from 'qrcode'
+import { prepareInvoicePdfRender, buildPaymentLinkQrDataUrl, buildSwishQrDataUrl } from '@/lib/invoices/pdf-render-helpers'
 import { makeCompanySettings, makeInvoice } from '@/tests/helpers'
 
 const fontDownloadMock = vi.hoisted(() => vi.fn())
@@ -336,3 +337,54 @@ describe('buildPaymentLinkQrDataUrl', () => {
     ).toBeNull()
   })
 })
+
+describe('buildSwishQrDataUrl', () => {
+  // Spy without replacing the implementation: the payload string is the unit
+  // under test (the PNG pixels are qrcode's concern), and the passthrough
+  // keeps the returned data URL real. The Swish payload locks the amount
+  // (editmask 0), so an amount above "Att betala" makes the customer overpay
+  // with no way to correct it in the app.
+  let toDataURL: MockInstance
+
+  beforeEach(() => {
+    toDataURL = vi.spyOn(QRCode, 'toDataURL')
+  })
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  const company = () => makeCompanySettings({ swish: '1234567890' })
+
+  it('encodes "Att betala" (total minus ROT/RUT deduction), not the invoice total', async () => {
+    const invoice = makeInvoice({ total: 1250, deduction_total: 625 })
+    const qr = await buildSwishQrDataUrl(company(), invoice)
+    expect(qr).toMatch(new RegExp(`^${PNG_DATA_URL_PREFIX}`))
+    expect(toDataURL).toHaveBeenCalledWith('C1234567890;625.00;F-2024001;0', expect.anything())
+  })
+
+  it('applies öresavrundning before the deduction, same order as the PDF totals block', async () => {
+    const invoice = makeInvoice({ total: 1250.49, ore_rounding: true, deduction_total: 625 })
+    await buildSwishQrDataUrl(company(), invoice)
+    expect(toDataURL).toHaveBeenCalledWith('C1234567890;625.00;F-2024001;0', expect.anything())
+  })
+
+  it('renders no QR when the deduction covers the whole invoice (nothing to pay)', async () => {
+    const invoice = makeInvoice({ total: 1250, deduction_total: 1250 })
+    expect(await buildSwishQrDataUrl(company(), invoice)).toBeNull()
+    expect(toDataURL).not.toHaveBeenCalled()
+  })
+
+  it('renders no QR for non-payable documents (credit note, proforma, delivery note)', async () => {
+    const creditNote = makeInvoice({ total: 1250, deduction_total: 625, credited_invoice_id: 'inv-orig' })
+    expect(await buildSwishQrDataUrl(company(), creditNote)).toBeNull()
+    expect(await buildSwishQrDataUrl(company(), makeInvoice({ document_type: 'proforma' }))).toBeNull()
+    expect(await buildSwishQrDataUrl(company(), makeInvoice({ document_type: 'delivery_note' }))).toBeNull()
+    expect(toDataURL).not.toHaveBeenCalled()
+  })
+
+  it('keeps the plain total for invoices without a deduction', async () => {
+    const invoice = makeInvoice()
+    await buildSwishQrDataUrl(company(), invoice)
+    expect(toDataURL).toHaveBeenCalledWith('C1234567890;12500.00;F-2024001;0', expect.anything())
+  })
+})