Build order and mapping notes

Phase	Parser family	Formats it covers	Mapping notes
1	ubl	Peppol BIS 3 + self-billing, XRechnung UBL, NLCIUS, CIUS-RO, CIUS-PT, HR-CIUS, OIOUBL 3, UBL.BE, PINT, BIS 2 (best-effort), OIOUBL 2	One parser, profile-specific rules on top. Invoice vs CreditNote element names differ (InvoicedQuantity/CreditedQuantity). UBL 2.1 CreditNote has no root cbc:DueDate: read cac:PaymentMeans/cbc:PaymentDueDate, and accept a root cbc:DueDate only as a fallback with a warning (it appears in some XRechnung test files).
1	cii	Factur-X/ZUGFeRD 2.x all profiles, XRechnung CII, NLCIUS CII, France CII	D16B and D22B share the root namespace. MINIMUM/BASIC WL have no lines.
2	fatturapa	FatturaPA, semplificata	Child elements are unqualified (no namespace). Several FatturaElettronicaBody per file. Natura → VAT category, RT0x → withholdings, cassa previdenziale → charge + extensions.it. SdI ID from the separate metadata file. Done: see src/parsers/fatturapa.ts (FPR12/FPA12 and FSM10; TD04/TD08 are credit notes; split payment → totals.splitPaymentVat; bollo → otherTaxes + extensions.it.stampDuty).
2	ksef	FA(2), FA(3), FA_RR	P_12 rate codes (23, zw, oo, np I, 0 WDT…) → VAT category. P_14_xW = VAT in PLN. StanPrzed → correctionState. Podmiot3 + Rola → additionalParties. KSeF number from download metadata.
2	facturae	Facturae 3.2–3.2.2	Batches (Modality L). TaxesWithheld → withholdings, recargo → otherTaxes. XAdES signature inside.
2	isdoc, ebinterface, finvoice, e-arve, eslog	National formats in active B2B use	ISDOC symbols → extensions.cz; ebInterface varies by version; Finvoice: SOAP + ISO-8859-15; e-arve: several invoices per file; eSLOG uses EDIFACT segment names (S_BGM, G_SG26…).
3	svefaktura, zugferd1, teappsxml, mydata, cfdi	Legacy and low-volume (cfdi is Mexican, see above)	Svefaktura follows SFTI’s “Mapping of Svefaktura 1.0 onto EN 16931-1” (see src/parsers/svefaktura.ts).

Done: ubl, cii, svefaktura and fatturapa. Corrective documents whose direction depends on the amounts (KSeF KOR, Facturae rectificativa, ISDOC) must set kind from the sign of the correction total; see effectiveSign() in src/canonical.ts.