perf(evm-wallet): make PBKDF2 iterations configurable, speed up crypto tests

[sirtimid]

Summary

The evm-wallet mnemonic encryption tests were taking ~250s combined (140s for mnemonic-crypto.test.ts, 110s for keyring-vat.test.ts) because they run PBKDF2 with 600,000 iterations — the production default — on every encrypt/decrypt call.

This PR adds an optional pbkdf2Iterations parameter to encryptMnemonic(), decryptMnemonic(), and keyring-vat's initialize() / unlock() methods. The parameter defaults to 600,000, so production behavior is unchanged. Tests now pass 1,000 iterations, reducing combined test time from ~250s to ~1.8s.

• Add optional pbkdf2Iterations parameter to encryptMnemonic() and decryptMnemonic(), defaulting to DEFAULT_PBKDF2_ITERATIONS (600,000)
• Thread the parameter through keyring-vat initialize() and unlock()
• Update all crypto-related tests to pass TEST_PBKDF2_ITERATIONS (1,000)
• Remove all 900_000ms test timeouts (no longer needed)

Test plan

All 36 tests across mnemonic-crypto.test.ts (8 tests) and keyring-vat.test.ts (28 tests) pass in ~1.8s total. The tests exercise the same encrypt/decrypt logic paths as before — only the iteration count differs, which doesn't affect correctness of AES-GCM encryption, key derivation structure, or error handling.

🤖 Generated with Claude Code

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Note

Medium Risk
Introduces a new optional security parameter (pbkdf2Iterations) to mnemonic encryption/decryption and keyring unlock/initialize; production defaults are unchanged but callers could accidentally use too-low iteration counts if misconfigured.

Overview
Makes PBKDF2 iteration count configurable for mnemonic encryption by adding an optional pbkdf2Iterations parameter to encryptMnemonic/decryptMnemonic (defaulting to 600,000) and threading it through keyring vat initialize and unlock.

Speeds up test suite by updating mnemonic/keyring crypto tests to use TEST_PBKDF2_ITERATIONS = 1_000 and removing the long per-test timeouts while keeping the same behavioral assertions (roundtrip, wrong password, tampering, deterministic output).

^{Written by Cursor Bugbot for commit 1fa27e3. This will update automatically on new commits. Configure here.}

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	78.15% 🟰 ±0%	8218 / 10515
🔵	Statements	77.96% 🟰 ±0%	8351 / 10711
🔵	Functions	75.54% 🟰 ±0%	1937 / 2564
🔵	Branches	76.6% ⬆️ +0.01%	3484 / 4548

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/evm-wallet-experiment/src/lib/mnemonic-crypto.ts	97.43% 🟰 ±0%	83.33% ⬆️ +8.33%	85.71% 🟰 ±0%	100% 🟰 ±0%	6
packages/evm-wallet-experiment/src/vats/keyring-vat.ts	88% 🟰 ±0%	82.85% 🟰 ±0%	100% 🟰 ±0%	87.87% 🟰 ±0%	137, 148, 196, 211, 216, 233, 237, 245, 250, 254, 272, 276

Generated in workflow #4120 for commit 1fa27e3 by the Vitest Coverage Report Action

[rekmarks]

LGTM!