bug: network fetch errors bubble up with no context

[satoshai-dev]

Description

fetch(url) can reject with a TypeError for network-level failures (no internet, DNS failure, ECONNREFUSED to devnet). The current code only handles HTTP status codes — network rejections propagate as raw TypeError: fetch failed with no context about which contract or network was being fetched.

Location

src/fetcher.ts:34 — const response = await fetch(url);

Suggested fix

let response: Response;
try {
  response = await fetch(url);
} catch (cause) {
  throw new Error(
    `Network error fetching ABI for ${address}.${name} on ${network}`,
    { cause },
  );
}