Add support to no tax code customer

[mrdanwa]

• Support Spanish customers to issue simplified invoices using passport
• Map identities country that was not mapped
• Use identities country to get IDType
• Adapt to new linter

[Copilot]

Pull request overview

This PR updates TicketBAI conversion to better support customers without a usable Spanish TaxID code (e.g., simplified invoices for Spanish customers identified via passport), and aligns tests with newer typed constants/linter expectations.

Changes:

• Treat Spanish customers with TaxID.Country=ES but empty TaxID.Code as “identified via identities” (e.g., passport) instead of forcing an empty NIF.
• Extend customer “other identity” mapping to populate CodigoPais from the identity’s country when present, and introduce partyCountry to derive country from either TaxID or identities.
• Update tests to use typed constants (e.g., tax.CategoryVAT, org.ItemKeyGoods) and add new conversion scenarios for passport/no-tax-code customers.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
convert/parties.go	Adjusts destinatario identification logic; adds partyCountry; maps CodigoPais from identity country.
convert/invoice.go	Uses partyCountry when deciding whether to add “export/foreign” VAT key.
convert/breakdown.go	Uses partyCountry to decide domestic vs foreign breakdown structure.
convert/doc_test.go	Adds test cases for Spanish passport customers and CodigoPais behavior.
convert/invoice_test.go	Introduces typed rate constants and updates tax/category usage in tests.
convert/lines_test.go	Updates tax category/rate constants usage in tests.
convert/breakdown_test.go	Updates item key and tax category/rate constants usage in tests.

Comments suppressed due to low confidence (2)

convert/invoice.go:156

• newClaves now uses partyCountry, which can return the customer's country from identities when TaxID is missing. This changes behavior for Spanish customers identified only via an identity with Country: "ES" (they should no longer get export key "02"). Add/adjust a test case covering Customer.TaxID == nil with an identity country of ES to ensure the expected clave is produced.

	claves := []IDClave{}

	if inv.Customer != nil && partyCountry(inv.Customer) != "ES" {
		claves = append(claves, IDClave{
			ClaveRegimenIvaOpTrascendencia: "02",
		})
	}

convert/breakdown.go:112

• newTipoDesglose now relies on partyCountry, which can classify a customer as Spanish based on identity country even when TaxID is nil. This is a functional change (e.g., Spanish passport customer with Identities[0].Country == "ES" should now produce DesgloseFactura instead of DesgloseTipoOperacion). Add a test covering this scenario to lock in the intended behavior.

	desglose := &TipoDesglose{}

	if gobl.Customer == nil || partyCountry(gobl.Customer) == l10n.ES.Tax() {
		desglose.DesgloseFactura = newDesgloseFactura(taxInfo, catTotal.Rates)
	} else {
		goods, services := splitByTBAIProduct(catTotal.Rates)

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[pmenendz]

LGTM, just solve the issue with gocosnt and add a test for the new use case in parties