Fix #3273: Refactor labeler.yml for improved automated PR labeling

[kutumia]

📄 Description

This PR improves GitHub workflow automation by updating .github/labeler.yml:

• Refactored labels into subcategories:
  • Docs/User
  • Scripts/R
  • Modules/Assimilation
  • and more.
• Enhanced pattern matching for automatic PR labeling.
• Improves developer experience by ensuring PRs are more accurately and consistently labeled.

These improvements help:

• Streamline contributor workflow
• Make triaging and reviewing PRs easier for maintainers

---

Fixes: #3273

[kutumia]

Hey team! This PR refactors the labeler config to be cleaner and more accurate with subcategories. Let me know if anything needs adjusting — happy to tweak it!

[infotroph]

Thanks for working on this! I think these categories do still need some tweaks.

The key question we should answer for each label we define is: Who will change their plans when we apply this label to a PR?

• If the assigned tags help Alice (the point person for component A) notice and quickly review a PR that touches component A, that's a success.
• If they help Bob (a new contributor working on component B) glance at the PR list and say "Oh, I don't need to click on that, I don't really work with component A", that's also a success.
• If the assigned tags are uninformative to both Alice and Bob and they both have to click through and read to decide what to do with the PR, or if the labels primarily duplicate information present in PR titles, that's a missed opportunity.

[allgandalf]

LGTM!, CI failure seems unrelated to our changes