EFT/Havale was retired; Stripe is now the sole payment method. Remove the
EFT code surface (shared PaymentMethod "eft" + EftPaymentInput + eftReceiptUrl,
EFT_RECEIPT_REQUIRED error code, billing UI receipt/filter/label paths,
payments.service eft read paths). DB columns (eft_receipt_url, bank_account_id,
bank_accounts) are kept and marked @deprecated to preserve historical records
and avoid a destructive migration — same pattern as the retired iyzico column.
Faz 3 conversion lever: set locale "tr" on the Stripe Checkout session. The
audience is Turkish B2B and ~60% of sessions reached the foreign-language
hosted page but never started a payment intent (pure abandonment, not decline).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>