fix(keystore): throw on address mismatch instead of silently warning

[amathxbt]

Bug

importFromGoKeystore() verifies that the address derived from the public key matches entry.keyAddress, but responds to a mismatch with only a console.warn. The mismatched entry is then silently returned to the caller using the stored (wrong) address.

Impact: A corrupted or tampered keystore entry is accepted without error. Subsequent transactions are built with an address that does not match the signing key, so they are either rejected by the network or—if the stored address belongs to a different key—send funds to an uncontrolled account.

Fix

Replace console.warn with a thrown Error that identifies both addresses. Callers that handle keystore entries should catch this to surface integrity failures before any funds are at risk.

// Before
console.warn(`Address mismatch: expected ${entry.keyAddress}, derived ${derivedAddress}`);

// After
throw new Error(
  `Keystore integrity check failed: stored address ${entry.keyAddress} does not match ` +
  `address derived from public key ${derivedAddress}. The keystore entry may be corrupted or tampered.`
);