SDK drift: `NotSupported` error `.code` is `"UNKNOWN_ERROR"` in Python but `"NOT_SUPPORTED"` in TypeScript

[realfishsam]

Summary

The NotSupported error class sets different .code values in the two SDKs.

SDK	File	Line	.code value
TypeScript	sdks/typescript/pmxt/errors.ts	121	"NOT_SUPPORTED" (explicit: super(message, "NOT_SUPPORTED", false, exchange))
Python	sdks/python/pmxt/errors.py	172	"UNKNOWN_ERROR" (inherits PmxtError default; no explicit code passed)

Reproduction

# Python
from pmxt.errors import NotSupported
e = NotSupported("test")
print(e.code)  # "UNKNOWN_ERROR"

// TypeScript
import { NotSupported } from "pmxtjs";
const e = new NotSupported("test");
console.log(e.code);  // "NOT_SUPPORTED"

Impact

Any cross-SDK error-handling code that switches on e.code == "NOT_SUPPORTED" will silently fail in Python — the Python instance will never match that check. This also means Python's _ERROR_CODE_MAP does not contain a "NOT_SUPPORTED" entry, so fromServerError/from_server_error cannot reconstruct a NotSupported from a wire error with code: "NOT_SUPPORTED".