Upgrade to Node 22 and clean up relevant code

[ecxyzzy]

Node.js 22 has just hit LTS, bringing with it some additional goodies like support for Iterator.toArray and Iterator.map.

We're also no longer constrained to Node 20, since Cloudflare has confirmed that using their codegen for types (which we are) means we do not need to pin the @types/node package to v20, so we can actually upgrade to Node 22.

Context

This will be useful in cleaning up components of our data pipelines, since we use the following pattern a lot:

const theMap = new Map<string, unknown>();

const res = Array.from(theMap.keys()).map((key) => { ... });

Which can then be converted into this pattern:

const theMap = new Map<string, unknown>();

// toArray can even be omitted in cases where the function consuming res accepts an Iterator
const res = theMap.keys().map((key) => { ... }).toArray();

Action Items

• Set version in .nvmrc to 22.11.0
• Install latest @types/node at workspace level
• Remove @types/node at package level
• Refactor code using Array.from
• Verify that nothing broke