Friendly address serialization (Address.toString()) correctly encodes negative workchains (e.g., -2) as signed 8-bit integers. However, the deserialization function (Address.parse()) misinterprets these encoded negative values as unsigned, corrupting the original workchain number.

Example:

import { Address } from "@ton/core";

const addr = new Address(-2, Buffer.alloc(32, 0));
const encoded = addr.toString();
console.log(encoded); // => "Ef4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAL3I" (correct for -2)

const decoded = Address.parse(encoded);
console.log(decoded.workChain); // => 254 (incorrect, should be -2)

Explanation:

• The serialized friendly address "Ef4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAL3I" is correctly encoded with the workchain byte 0xFE, representing -2 in signed 8-bit form.
• Address.parse incorrectly treats this signed byte as an unsigned value (254), resulting in an incorrect workchain upon parsing.

Expected Behavior:
Address.parse must interpret the workchain byte as a signed integer, correctly restoring the original negative value.

LLM Fuzzing discovery (see tact-lang/tact#3123)