Update Polymarket documentation - April 9, 2026

Changes:
- Changelog: Added Apr 9, 2026 entry - GET /markets: closed defaults to false
- list-markets.md: Updated to reflect closed=false default on the 'closed' query parameter
- New endpoint: Added get-batch-prices-history.md (POST /batch-prices-history)
- TARGET.md: Added new get-batch-prices-history.md URL

docs/api-reference/markets/list-markets.md

@@ -159,6 +159,7 @@ paths:
           in: query
           schema:
             type: boolean
+            default: false
       responses:
         '200':
           description: List of markets
@@ -972,10 +973,6 @@ components:
           type: string
           format: date-time
           nullable: true
-        updatedAt:
-          type: string
-          format: date-time
-          nullable: true
     Tag:
       type: object
       properties:
@@ -1003,10 +1000,6 @@ components:
           type: string
           format: date-time
           nullable: true
-        updatedAt:
-          type: string
-          format: date-time
-          nullable: true
         forceHide:
           type: boolean
           nullable: true
@@ -1100,10 +1093,6 @@ components:
           type: string
           format: date-time
           nullable: true
-        updatedAt:
-          type: string
-          format: date-time
-          nullable: true
         commentsEnabled:
           type: boolean
           nullable: true
@@ -1230,10 +1219,6 @@ components:
           type: string
           format: date-time
           nullable: true
-        updatedAt:
-          type: string
-          format: date-time
-          nullable: true
         commentsEnabled:
           type: boolean
           nullable: true