fix(payments): creditor address per Swedbank TwnNm rule (Validex round 2) (#1508)

A present PstlAdr must carry TwnNm from November 2026 (PFH_222), so
BGNR-to-BGNR payments now carry no creditor address at all (rule 020
requires none there), IBAN-debited payments carry the supplier's town
(snapshotted as payee_city) plus Ctry SE, and the debtor address comes
from company settings, clearing the info-level rule 236 as well.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

DECISIONS.md

@@ -857,3 +857,4 @@ One line per decision: `[YYYY-MM-DD] <decision>: <why>`. Appended by agents and
 [2026-08-10] Atom seed migrations gained a version-downgrade guard in the generator (#1483): each seed is a full 108-atom upsert built from its branch's tree, so two parallel PRs each carrying a seed meant the last-applied one silently reverted the other's atom bodies while skills:check stayed green (it compares files to the manifest, never the DB). The ON CONFLICT now skips rows whose registry version is newer than the seed's. Dance-event VAT stayed guidance-plus-descriptor only: no rate cutover logic in the engine, since 6% already exists as a treatment and the entry date decides the rate the user picks.
 [2026-08-10] Supplier betalfil (payment batches) ships pain.001.001.03 ONLY, no Bankgirot LB generator (founder call via scope questions): at ship time LB is dead at Handelsbanken/SEB and dies at Swedbank for supplier files 1 Sep 2026; Danske replaces LB with ISO 20022 during its Apr-Nov 2026 modernisation window without publishing a per-format date (27 Nov 2026 = all file communication must go via the bank; verified against danskebank.se 2026-08-10 after a bot review claimed 12 May, which is actually the bankgiro-alias initiation date). An LB path would have weeks of shelf life at the majors; the DB format CHECK still allows 'bg_lb' so a future LB or pain.001.001.09 addition needs no migration, the API Zod schema gates to 'pain001'. The supplier pain.001 generator (lib/payments/pain001-supplier.ts) reimplements the four tiny XML helpers instead of exporting them from lib/salary/payment/pain001-generator.ts: ~40 duplicated lines beat destabilizing a production-hardened salary dialect (2026-07-12 entry), and the two dialects genuinely differ (supplier files carry RmtInf SCOR/Ustrd and giro creditor addressing SESBA 9900 BGNR / 9960 BBAN; salary forbids RmtInf and marks CtgyPurp SALA). splitDomesticBankAccount IS shared so account routing can never diverge. Batches fix the documented no-regeneration-guard hazard (2026-07-26 entry) by construction: msg_id derives from the batch id at creation and CreDtTm from created_at, so re-download is byte-identical (bank dedup on MsgId works) and only a new batch mints a new MsgId. Generating/downloading a file books nothing: settlement stays in mark-paid/bank-match, matching the help_body direction that payment truth comes from the bank.
 [2026-08-10] Supplier pain.001 dialect corrected against a real Swedbank Validex run (MIG 1.0, eken.validex.net), which is stricter than the Bankforeningen appendix the generator was built from. Four generator changes: (1) MIG character set enforced by transliteration (a-acute to a, ampersand to plus, Swedish aao survive; leftovers become '?', matching LB padText), because rule 214 rejects e-acute in names outright; (2) InitgPty/Dbtr OrgId is now mandatory and the batch service refuses companies without organisationsnummer (rule 002), reading settings.org_number before the write-once companies.org_number; (3) BGNR creditors debit the company bankgiro when one exists, in their own PmtInf per (date, debit-form) group, because rule 219 demands BGNR-to-BGNR, with Cdtr PstlAdr/Ctry SE always present so IBAN-debited giro payments stay valid under rule 020 (v1 is domestic-only); (4) Strd carries RfrdDocAmt/RmtdAmt = the instructed amount (rule 217). Consequence accepted: the byte-identical re-download contract holds per generator version, not across dialect fixes; MsgId is unchanged so bank-side dedup still keys correctly. Validex account creation has a reCAPTCHA that was deliberately not circumvented; the founder registers and uploads.
+[2026-08-10] Validex round 2 (1 fatal left): a present PstlAdr must carry TwnNm from November 2026 (rule 222), and the round-1 fix had added Ctry-only creditor addresses everywhere. Resolution follows Swedbank's own conditionality instead of stuffing TwnNm in unconditionally: BGNR-to-BGNR payments carry NO creditor address (rule 020 does not require one there), IBAN-debited payments carry the supplier's town (new nullable supplier_payment_batch_items.payee_city snapshot) plus Ctry SE, and the debtor gains PstlAdr TwnNm/Ctry from company_settings.city, which also clears the info-level rule 236. Rule 183 (BIC must be SWEDSESS) fires only because the sandbox debtor is a fake SEB account; real Swedbank customers resolve SWEDSESS from their own settings.