Proposal: add GitHub-native citation support (CITATION.cff + bilingual README section)

[ulissesflores]

Hi! I'd like to contribute a small documentation-only improvement to make MiroFish easier to cite in academic work.

Proposal:

• add a CITATION.cff file for GitHub-native citation support
• add a short citation section to README.md and README-EN.md

Why this may help:

• makes MiroFish easier to cite in papers, theses, and software reports
• enables GitHub's native "Cite this repository" interface
• does not change code, architecture, authorship, or project branding
• does not require Zenodo or any release workflow changes

Scope:

• documentation only
• no code changes
• no dependency or deployment changes

If this sounds useful, I can open a very small PR with only these changes.