feat: initial polymarket copy trade tool

- Watcher: polls Data API for trader activity
- Executor: buy/sell with market orders + retry logic
- Position manager: JSON-based state tracking
- Auto-sell: limit orders at profit target
- Redeemer: check & redeem winning positions on-chain
- Config: env-based settings with validation
- DRY_RUN mode for safe testing

.gitignore

@@ -0,0 +1,4 @@
+node_modules/
+.env
+data/*.json
+.DS_Store