feat(resolution): add automatic market resolution detector with conservative payout validation

- PolymarketClient.get_market_resolution(): query Gamma API by market id;
  resolved only when closed AND uma status final AND outcome prices binary
  (never settle on disputed/ambiguous outcomes)
- bot/main.py: check_resolutions() runs every 10 cycles (~10 min) in paper
  mode, settles open positions via PaperExecutor.close_position()
- close_reason now persisted as 'resolved' (resolution has its own column)
- tests/test_resolution_detector.py: 10 tests covering API parsing shapes
  and the BUY_NO settlement flow; 27/27 suite green

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bot/executor/paper.py

@@ -270,7 +270,7 @@ class PaperExecutor:
 
         await self._db.close_paper_position(
             market_id,
-            reason=f"market_resolved resolution={resolution:.1f}",
+            reason="resolved",
             resolution=resolution,
         )
         log.info(