[Draft] Fungible Agent Tokens (FAT) — a minimal standard for AI agents

FAT protocol standardizes AI agents as on-chain economic entities with three layers: autonomous execution, equity issuance via fungible Shares, and reasoning attestation. Agents accept single ERC-20, use two-phase request-then-claim mint/redeem, expose canonical exchange rate, and attach tamper-evident reasoning hashes. Interface fixes execution, pricing, and policy surfaces; implementers choose formulas and fee structures.