feat(cpe): NC + ND end-to-end via sunat-direct, verified live

[Railly]

Summary

Closes the SOAP CPE emission cycle. Verified accepted by SUNAT beta 2026-04-29:

✅ NC: FC01-555 → cdrCode=0 "La Nota de Credito ... ha sido aceptada"
✅ ND: FD01-777 → cdrCode=0 "La Nota de Debito ... ha sido aceptada"

Now sunat-direct supports the full Factura → Boleta → NC → ND lifecycle. Driver matrix in LIMITATIONS.md flips NC/ND from 🚧 to 🔬.

What's in this PR

UBL builders

• src/cpe/ubl/nota-credito.ts — CreditNote-2 schema (NOT Invoice-2)
• src/cpe/ubl/nota-debito.ts — DebitNote-2 schema with RequestedMonetaryTotal (NOT LegalMonetaryTotal — SUNAT-specific divergence)

Differences from Factura that bite if you don't know:

• NC line tag: CreditNoteLine + CreditedQuantity
• ND line tag: DebitNoteLine + DebitedQuantity
• ND totals: RequestedMonetaryTotal (not LegalMonetaryTotal)
• Both add cac:DiscrepancyResponse (refDoc + ResponseCode + motivo)
• Both add cac:BillingReference with DocumentTypeCode auto-detected from refSerie prefix (F→01 Factura, B→03 Boleta)

Reuse common.ts helpers + tag-swap on renderInvoiceLine output.

Validation

• validateNotaCredito (Catálogo 09, 13 codes)
• validateNotaDebito (Catálogo 10, 5 codes)
• Shared validateNotaCommon covers serie format, ref fields, motivo length, RUC/DNI receptor, items/totales coherence, moneda
• Catalog 09 ↔ 10 enforcement: NC's 06 (Devolución total) is rejected for ND

Driver

• emitNotaCredito + emitNotaDebito share private emitNota(input, "07"|"08")
• Reuses sendBill, idempotency cache, two-phase audit from factura/boleta
• Filename: RUC-07-... (NC) / RUC-08-... (ND)
• Audit commands: cpe nc emit / cpe nd emit

Commands

• cpe nd emit now real (was stub). cpe nc emit already wired in PR feat(cpe): CPE namespace + sunat-direct driver (Factura, verified end-to-end) #1.

Tests

325 pass / 2 skip / 0 fail in 3.1s (was 283)

ubl-nota-credito.test.ts (12):
- Root NS CreditNote-2 + no Invoice tags
- ID format serie-numero
- DiscrepancyResponse + BillingReference (F→01, B→03 auto-detect)
- CreditNoteLine + CreditedQuantity (no InvoiceLine/InvoicedQuantity)
- ext:UBLExtensions placeholder
- LegalMonetaryTotal carries totals (NC keeps this, ND doesn't)
- Multi-line count

ubl-nota-debito.test.ts (8):
- Root NS DebitNote-2
- DebitNoteLine + DebitedQuantity
- RequestedMonetaryTotal (NOT LegalMonetaryTotal)
- DiscrepancyResponse + BillingReference detect
- ID format
- ext placeholder
- Multi-line

reglas-nota.test.ts (15):
- Happy paths NC + ND
- All 13 codes in Catálogo 09 accepted for NC
- All 5 codes in Catálogo 10 accepted for ND
- Code valid in 09 ("06" Devolución) rejected for ND
- Series format both F* and B*
- ref* required
- motivo length ≤ 250
- RUC checksum, fechaEmision plazo, totales coherence

Verified end-to-end against SUNAT beta

$ CPE_PROFILE=test ... bun run bin/sunat.ts cpe --driver sunat-direct nc emit --params '...' --yes
{ success: true, status: "accepted", cdrCode: "0",
  cdrDesc: "La Nota de Credito numero FC01-555, ha sido aceptada", ... }

$ ... cpe --driver sunat-direct nd emit --params '...' --yes
{ success: true, status: "accepted", cdrCode: "0",
  cdrDesc: "La Nota de Debito numero FD01-777, ha sido aceptada", ... }

Same Greenter test cert + RUC 20000000001 from PR #1. Both first-try.

LIMITATIONS.md updated

• Driver matrix: sunat-direct × NC/ND → 🔬 (verified)
• Active limitations section: NC/ND moved from "shaped" to "shipped + verified"
• Verified end-to-end list: 4 SUNAT beta successes catalogued (factura, boleta, NC, ND)

Out of scope (still in LIMITATIONS)

• 🚧 cpe void T3 with intent token (today voiding goes via NC for facturas, Comunicación de Baja for boletas)
• 🚧 Drivers facturador, nubefact, apisperu for NC/ND (mock + sunat-direct only)
• 🚧 NC special cases: line-level (codes 05/07), bonificación (08), exportación (11), IVAP (12) — schema accepts them but no targeted validation yet

Test plan

• bun test green (325/2 skip/0 fail)
• cpe nc emit accepted by SUNAT beta (FC01-555, cdrCode=0)
• cpe nd emit accepted by SUNAT beta (FD01-777, cdrCode=0)
• validateNotaDebito rejects code "06" (which is valid for NC but not ND)
• BillingReference detects F→01 and B→03 from refSerie prefix
• LIMITATIONS.md driver matrix updated to 🔬
• CI green on push