[PLUGINS] Add metadata lint rules for missing field help text and ambiguous categories

[utksh1]

Summary

Metadata quality problems such as missing help text and fuzzy category assignment are currently found by manual review instead of automated checks.

Scope

• Extend the plugin validation workflow to flag low-quality metadata.
• Start with checks that are objective and low-noise.
• Document any new validation rules for contributors.

Acceptance criteria

• At least one automated metadata quality check is added.
• The rules are documented for contributors.
• Existing plugins can be brought into compliance incrementally.

[anshul23102]

Interested in contributing to this under NSoC'26. This is a valuable issue addressing important functionality/quality. Happy to take this on.

/assign

[anshul23102]

Interested in contributing under NSoC'26. This is a valuable issue. Happy to work on it.

/assign

[Pcmhacker-piro]

Hi @utksh1 ,

I’d like to contribute to this project by working on this issue. I have experience contributing to open-source projects and would be glad to take ownership of the required implementation.

Kindly assign this issue to me if it’s available. Thank you!

[Pcmhacker-piro]

Implemented in PR #789.

• Automated checks added: category validation (_check_category) + missing help text lint
• Warning-level (non-blocking): help text lint uses the new ValidationResult.warnings list, so existing plugins remain valid
• Documented: the rules are documented in PLUGINS.md
• Existing plugins can comply incrementally: the help text check is a non-blocking warning; unknown categories produce a clear error message