Add ERC: Preregistered Acceptance Criteria

assets/erc-8412/.gitignore

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+__pycache__/
+*.pyc

assets/erc-8412/README.md

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+# ERC-8412 reference implementation and conformance vectors
+
+Everything here is CC0, like the specification.
+
+```
+contracts/
+  PreregisteredCriteria.sol   reference registry (§6, E1–E14)
+  test/Vectors.t.sol          GENERATED Foundry suite: every on-chain vector on the EVM
+  foundry.toml
+model/
+  registry.py                 executable model of the registry, mirrors the contract
+  ethcrypto.py                dependency-free keccak256, secp256k1, EIP-712, JCS
+  test_ethcrypto.py           known-answer tests against published vectors
+verifier/
+  verify.py                   reference off-chain verifier (O1–O5 and document checks)
+vectors/
+  onchain/<INV>.json          cases for E1–E14, duplicate and id rules, positive paths
+  offchain/<name>.json        complete document packages for O1–O5 and well-formedness
+tools/
+  run_all.py                  runs every check below
+  gen_onchain_vectors.py      builds on-chain vectors, validated against the model
+  gen_offchain_vectors.py     builds off-chain packages, validated against the verifier
+  gen_foundry_tests.py        translates on-chain vectors into Vectors.t.sol
+  mutation_test.py            proves every invariant is exercised
+```
+
+## Run
+
+No dependencies beyond Python 3.10:
+
+```
+python tools/run_all.py
+```
+
+On the EVM with Foundry:
+
+```
+cd contracts
+forge install foundry-rs/forge-std --no-git
+forge test
+```
+
+`Vectors.t.sol` places the registry at the vectors' registry address and sets
+the vectors' chain id, so the `preregistrationId` in `ID.json` matches byte for
+byte.
+
+## Vector format
+
+**On-chain** (`vectors/onchain/*.json`): a list of cases. Each case names the
+invariant it targets and a level (`MUST` or `SHOULD`), and is a sequence of
+steps with a block timestamp, a sender, arguments and an expectation.
+`"$p1"` refers to the `preregistrationId` bound by an earlier step. Actors are
+EOAs derived as `vm.addr(uint256(keccak256("erc8412:<name>")))`; `zero` is
+`address(0)`. A step expecting `revert` must revert; the tag records which
+invariant the case targets, but conformance does not depend on the revert
+reason, since implementations may check invariants in a different order.
+
+**Off-chain** (`vectors/offchain/*.json`): one package per file: on-chain
+state, criteria document, evidence bundle and attestation document, with real
+keccak256 digests and real EIP-712 waiver signatures. `expect.violations` lists
+the rules a conforming checker must report. `chainAccepts` records whether the
+registry alone would accept the same preregistration and attestation. For
+every refuted package in this set it would, which is why §8 exists.
+
+## What mutation testing shows
+
+`tools/mutation_test.py` switches off one invariant at a time in the model and
+re-runs every on-chain vector. Each mutation must make at least one vector fail.
+It also replays the pre-fix expiry text (`resolveExpired` allowed at
+`block.timestamp == expiry`, no terminal-verdict guard) and confirms the vectors
+catch the overwrite reported in review.
+
+## Scope notes
+
+- The off-chain verifier mechanises O2 only as far as documents allow:
+  required capture-metadata keys, `notBefore`, `mediaType`. It does not open
+  salted commitments or inspect media.
+- O4 is mechanised for the standard decision rules. Namespaced rules are
+  reported as unchecked rather than refuted.
+- `ethcrypto.py` exists so the vectors can be generated and checked without
+  third-party packages. It is not constant-time and is not for production keys.
+- The contract is reference code: unaudited and not gas-optimised.

assets/erc-8412/contracts/.gitignore

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+# Foundry dependencies and build output: never commit
+lib/
+out/
+cache/
+broadcast/