Support Node.js in source code / line-by-line integration

The line-by-line source code integration only supports Go, Java, and Python.

**Node.js apps profiled with @pyroscope/nodejs have no way to link a function back to the exact source line in GitHub, unlike the supported languages.**

doc: https://grafana.com/docs/pyroscope/latest/view-and-analyze-profile-data/line-by-line/

- Support service_repository / service_git_ref / service_root_path tags for Node.js profiles, same as Go/Python.
- Automatic file path resolution for .js/.ts, with source map support for transpiled/bundled TS.
- .pyroscope.yaml mapping support consistent with existing languages.

Start by tracing the existing Go, Java, and Python line-by-line integrations and the linked documentation. Check how Node.js profiles expose service_repository, service_git_ref, and service_root_path, then investigate .js/.ts path resolution, source maps, and .pyroscope.yaml mappings. Done means Node.js profiles link functions to exact GitHub source lines consistently with the supported languages.

Written by the indexing model from the issue text.