fix(core): wire-format reset — BLAKE3 block hash, PQTX domain prefix, 16-byte AA domains, 32-byte address wire

[LucienSong]

Summary

Phase 2 of the white-paper alignment plan. Stages breaking wire-format changes ahead of the single testnet restart after Phase 5.

Changes

1. Block hash → BLAKE3 canonical encoding (WP §1489-1499)

• BlockHeader::hash() now returns blake3(canonical_encode(header)) instead of keccak256(rlp(header))
• canonical_encode() produces a fixed 424-byte deterministic preimage:
  • 16-byte domain: SHELL_BLOCK_HDR\0
  • 11 × 32-byte hash fields (variable-length fields committed as BLAKE3 hash)
  • 7 × 8-byte LE u64 fields
• Added header_canonical_encode_len() test asserting exactly 424 bytes

2. PQTX signing envelope domain prefix (WP §1503-1509)

• Transaction::signing_hash() preimage now starts with PQTX_SIGNING_V1\0 (16 bytes)
• SDK golden vector updated: 0xf5a1…0836 → 0x68ee…4761
• Note: shell-sdk's hashTransaction() must be updated to prepend the same 16-byte domain

3. 16-byte AA signing domains

Upgraded from 1-byte to 16-byte domain strings across all AA signing paths:

Function	Old	New
batch_signing_hash()	0x7E	PQTX_BUNDLE_V1\0\0
paymaster_signing_hash()	0x7F	PQTX_PAYMASTER_V
SessionAuth::auth_hash()	0x81	PQTX_SESSION_V1\0

• Removed legacy BATCH_SIGNING_HASH_DOMAIN, PAYMASTER_SIGNING_HASH_DOMAIN, SESSION_AUTH_HASH_DOMAIN u8 constants
• Exported new 16-byte constants from shell-core crate root

4. 32-byte address enforcement on wire (remove 20-byte decode fallbacks)

• InnerCall::decode() — rejects 20-byte to address; only 32-byte or empty accepted
• Transaction::decode() — rejects 20-byte to address
• AaBundle::decode() — rejects 20-byte paymaster address
• SessionAuth::decode() — rejects 20-byte target address
• SessionAuth::auth_hash() — None target now pads to [0u8; 32] (was [0u8; 20])

Test results

test result: ok. 220 passed; 0 failed; 0 ignored

Downstream impact

• shell-sdk: hashTransaction() must prepend PQTX_SIGNING_V1\0 (16 bytes) before chain_id
• All clients: block hash algorithm change takes effect immediately on merge; any cached block hashes are invalid
• Testnet restart: scheduled after Phase 5 (single restart covers all Phase 2–5 wire changes)

[Copilot]

Pull request overview

Stages Phase 2 whitepaper-alignment breaking wire-format changes by switching block hashing to a BLAKE3 canonical encoding, introducing PQTX/AA 16-byte domain prefixes for signing hashes, and enforcing 32-byte addresses on the wire (removing 20-byte decode fallbacks). This affects core hashing/signing primitives and transaction/session/bundle decoding behavior, with small follow-up adjustments in node/consensus code and test vectors.

Changes:

• Switch BlockHeader::hash() to blake3(canonical_encode(header)) with a fixed-width (424B) canonical preimage.
• Add PQTX domain prefixing for transaction signing + move AA signing domains to 16-byte tags; update golden vectors accordingly.
• Enforce 32-byte addresses in decode paths for Transaction, InnerCall, AaBundle, and SessionAuth (reject legacy 20-byte inputs).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/core/src/block.rs	Introduces canonical 424-byte block-header encoding and updates block hash to BLAKE3 over that encoding; adds length test.
crates/core/src/transaction.rs	Adds PQTX signing domain prefix, upgrades AA signing domains to 16 bytes, and removes 20-byte address decode fallbacks across multiple wire decoders.
crates/core/src/lib.rs	Re-exports new PQTX/AA domain constants from the core crate root and removes legacy u8 domain exports.
crates/core/tests/sdk_vectors.rs	Updates SDK golden vector to match the new PQTX signing preimage domain prefix.
crates/node/src/node/event_loop.rs	Avoids cloning the finalized hash by copying the ShellHash value directly.
crates/node/src/node/p2p_handlers.rs	Formatting-only change around attestation signing message construction.
crates/consensus/src/wpoa.rs	Adjusts imports and formats test calls (no functional behavior change intended).
crates/consensus/src/view_change.rs	Formatting-only change for own_signing_message() call site.
crates/consensus/src/finality.rs	Formats test helper + attestation signing message calls (no functional behavior change intended).

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