Add docs for querying frontend/javascript sourcemaps

[tommymarshall]

How can we make our docs better?

It's unclear if the sourcemaps API (https://sourcemaps.service.newrelic.com/v2/applications/**Account ID**/sourcemaps) accepts any arguments other than limit and offset. By default, sourcemaps appear unordered. A workaround I'm using is passing a huge limit (probably a bug?) and filtering the output manually 🤷 .

Searching query docs for anything sourcemap related on the Nerdgraph also returns empty.

Existing AI tools (Claude, Grok, etc.) hallucinate expecting certain fields to be queryable (using the New Relic GraphQL API or the v2 endpoint), but are not available or not documented.

This combination makes frontend error tracking feel like an afterthought/ignored from New Relic's team.

[github-actions]

Hi @tommymarshall 👋

Thank you for filing an issue! We'll triage your issue and let you know if we have questions, and then route it to the appropriate team so we can get it solved.