CECHO-1425

@claude review this PR as grug

Claude finished @ArunBala-Bitgo's task —— View job

Grug Review Time

Grug review PR as requested. Grug make todo list:

• Read repo instructions (CLAUDE.md)
• Look at all changed files
• Check if fix make sense for problem
• Give grug opinion on code
• Update comment with review

Grug Brain Analysis

Grug look at code. Grug think simple thoughts. Here what grug find:

Problem 1: Missing isSignablePreHashed

File: modules/sdk-coin-flr/src/flr.ts:96-98

Grug see good fix! FLR C->P atomic transaction already has SHA-256 hash. MPC signing no need rehash with keccak256. Code simple:

isSignablePreHashed(unsignedTx: SignableTransaction): boolean {
  return isAvalancheAtomicTx(unsignedTx);
}

Grug like. Function do one thing. Return true when atomic transaction. Return false when normal EVM transaction. Simple logic. Good docstring explain why.

Problem 2: TSS recipient guard blocks import intents

File: modules/sdk-core/src/bitgo/utils/tss/recipientUtils.ts:65-66

Grug see good fix! Add 'import' and 'importtoc' to NO_RECIPIENT_TX_TYPES set. These transactions import wallet's own UTXOs. No external recipient needed. Comment explain good:

// Avalanche / Flare cross-chain atomic imports — recipients are not supplied
// by the client because the import consumes UTXOs already owned by the
// wallet; the destination address is the wallet itself.

Grug understand. When wallet import own money, no need specify recipient. Wallet already know where money go (to itself).

Tests Look Good

Files: Test files have good coverage

Grug see tests for both fixes:

1. isSignablePreHashed tests atomic vs normal transactions
2. NO_RECIPIENT_TX_TYPES tests include new import types
3. Tests verify no error thrown for import intents

Grug approve test strategy. Test what break, test what fix.

Grug Concerns

Minor: Grug notice NO_RECIPIENT_TX_TYPES has both 'enableToken' and 'enabletoken' (lines 26-27). Same with 'disabletoken'. Grug wonder if this intentional or typo? But this not part of current PR, so grug not worry.

Good: Code style consistent with rest of codebase. Comments explain business logic well. Changes minimal and focused.

Grug Verdict: GOOD FIX

Problem: Two signing ceremony failures

1. ❌ MPCv2 rehashes atomic transaction hash → signature shares no combine
2. ❌ TSS guard blocks import intents → "Recipient details required" error

Solution:

1. ✅ Add isSignablePreHashed to prevent rehashing
2. ✅ Add import types to NO_RECIPIENT_TX_TYPES to allow imports

Grug think fix correct. Code simple. Tests good. Will solve both problems described in PR.

Grug give thumbs up 👍