docs: add TypeScript generator for human-friendly OSS Directory schema docs

[VinitaSilaparasetty]

What

• Add scripts/generate-schema-docs.ts: TypeScript generator that produces a single, human-readable Markdown page from local JSON Schemas (project, collection).
• Output: docs/oss-directory-schema.md.
• No runtime deps; run via npx tsx.

Why

• Improves readability over default generators (clear titles, array handling, examples, constraints).
• Keeps docs tied to the source schemas; re-generate after schema changes.

How to run

• npx tsx scripts/generate-schema-docs.ts

References

• Related to OSS Directory schema markdown generator oso#3048

[VinitaSilaparasetty]

@ryscheng @ravenac95 I gave it another go, this time with a simpler solution. I'm grateful for any feedback that you can provide.