Validate a BIC/SWIFT code (ISO 9362) deterministically: 8 or 11-char structure, bank code, ISO 3166 country check, location + branch decode, and live/test/passive status flag. Zero external dependencies, no hallucination. Completes the IBAN + US-routing payment-validation suite. Ed25519-signed. 0.001 USDC on Base. First 3 calls FREE per wallet — send header X-WALLET: 0x<your Base address> (no payment); then per call.