Adds a new market-data/polymarket skill for querying Polymarket's public
prediction market APIs. Pure read-only, zero authentication required,
zero external dependencies (stdlib only).
Includes:
- SKILL.md: Agent instructions with key concepts and workflow
- references/api-endpoints.md: Full API reference (Gamma, CLOB, Data APIs)
- scripts/polymarket.py: CLI helper for search, trending, prices, orderbooks,
price history, and recent trades
Addresses #589.
313d522b61