Add Ontoly Software Graph skill to seed data

[0xsarwagya]

Summary

• Add Ontoly Software Graph to the curated seed source.
• Regenerate scripts/seed-data.json with the new skill entry.
• Use zeroed usage/rating metrics rather than inventing popularity data.

Validation

• node scripts/build-seed-data.mjs
• python3 -c 'import json; json.load(open("scripts/seed-data.json")); print("seed-data.json valid")'
• git diff --cached --check