feat(cloudflare): Read wrangler config and resolve the Sentry options module

[JPeer264]

(replaces #22291)

part of #22066

Add the building blocks the auto-instrument Vite plugin will use, with no wiring into a plugin yet:

• wranglerConfig: locate and parse wrangler.{json,jsonc,toml} via wrangler's own unstable_readConfig, returning the worker entry (main) and the configured Durable Object class names.
• instrumentFile: find a conventional instrument.server.{ts,js,mjs,cjs} next to the entry and build the options import, falling back to an env-based callback when absent.
• defineCloudflareOptions: identity helper that gives the options callback its type in that module.

Adds wrangler as an optional peer dependency (used to read the config).

The instrument.server.* config can and should be written like the following:

import { defineCloudflareOptions } from '@sentry/cloudflare';

export default defineCloudflareOptions((env) => ({
  dsn: env.SENTRY_DSN,
  tracesSampleRate: 1.0,
}));

defineCloudflareOptions is only adding typings for env so it is easier it can also be used like the following:

import { defineCloudflareOptions } from '@sentry/cloudflare';

export default defineCloudflareOptions({
  dsn: env.SENTRY_DSN,
  tracesSampleRate: 1.0,
});

or

import type { CloudflareOptions } from '@sentry/cloudflare';

export default {
  dsn: env.SENTRY_DSN,
  tracesSampleRate: 1.0,
} satisfies CloudflareOptions;

Future possibilities

For now there is a shared config for all instrumentations. In the future there would be the possibility to have different exports and map them to the actual bindings. E.g.:

import { defineCloudflareOptions } from '@sentry/cloudflare';

// specifically for the durable object called `MY_DURABLE_OBJECT`. This is defined in the wrangler config
export const MY_DURABLE_OBJECT = defineCloudflareOptions((env) => ({
  dsn: env.OTHER_SENTRY_DSN,
  tracesSampleRate: 0.5,
}));

// for the default worker and all the other bindings
export default defineCloudflareOptions((env) => ({
  dsn: env.SENTRY_DSN,
  tracesSampleRate: 1.0,
}));

[timfish]

If you don't pass a config path, it says that wrangler will find the config. Would it be better to rely on the wrangler resolution?

[JPeer264]

great suggestion, with that it gets way cleaner

[JPeer264]

Ok I'll change that in a follow up PR. it gets too much of a mess with this stack otherwise

[timfish]

We just dropped Node v18 testing so this entre line might be redundant?

[JPeer264]

True, I'll remove this. I think this can also be cleaned up entirely ?
I could do this in a separate PR