feat(salary): skattekonto payment file as ISO 20022 pain.001 (#1845)

The tax payment file (skatt + arbetsgivaravgifter to Skatteverket BG
5050-1055) was Bankgirot LB only; banks that take pain.001 for salary,
like SEB via file communication agreements, refuse the LB .txt. The
route now accepts ?format=pain001 and generates the payment through the
supplier-payment pain.001 generator, whose Swedish giro dialect
(BG payee + SCOR OCR, Validex-validated) is exactly this payment shape.

The TaxPaymentPanel gets the same format selector as the salary
PaymentFilePanel, seeded from company_settings.preferred_payment_format,
with the missing-sender warning per format (bankgiro for LB, IBAN for
pain.001). A migration widens the tax_payment_file_format CHECK to
admit 'pain001'; bg_lb stays the default for old clients.


Claude-Session: https://claude.ai/code/session_01DUB7L8DbVP2icn8ZpoPkoE

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

supabase/migrations/20260824120000_agi_tax_payment_format_pain001.sql

@@ -0,0 +1,16 @@
+-- Allow ISO 20022 pain.001 as a tax payment file format.
+--
+-- The skattekonto payment file (skatt + arbetsgivaravgifter to Skatteverket
+-- BG 5050-1055) was Bankgirot LB only; banks are sunsetting LB file uploads
+-- during 2026 and companies on pain.001 for salary need the same format for
+-- the tax payment. The route now generates either format, so the CHECK on
+-- agi_declarations.tax_payment_file_format must admit 'pain001'.
+
+ALTER TABLE public.agi_declarations
+  DROP CONSTRAINT IF EXISTS agi_declarations_tax_payment_format_check;
+
+ALTER TABLE public.agi_declarations
+  ADD CONSTRAINT agi_declarations_tax_payment_format_check
+  CHECK (tax_payment_file_format IS NULL OR tax_payment_file_format IN ('bg_lb', 'pain001'));
+
+NOTIFY pgrst, 'reload schema';