Scope verifier replay protection by airnode

[saviro-orin]

Problem

Replay protection used only the signed payload hash. An unrelated signer could consume another signer’s replay slot, and a caller could burn valid data against an unrelated callback or selector.

Changes

• scope replay state by signer
• scope precise delivery replay state by signer, payload, callback address, and selector
• preserve fulfilled(airnode, requestHash) as an informational compatibility getter
• add tests proving independent signers, callbacks, and selectors cannot block each other
• update consumer documentation

Verification

• 43 Foundry tests passed, including new callback/selector burn regressions
• invariant suites passed
• Slither analyzed 4 contracts with 101 detectors and reported 0 findings
• book production build passed

Compatibility

The enforcement semantics change intentionally. Existing fulfilled(address,bytes32) callers remain source-compatible; fulfilledDelivery(bytes32) exposes the precise delivery state.