Update Polymarket documentation (2026-02-19)

- Added new documentation URLs from llms.txt index
- Updated TARGET.md with 244 total documentation pages
- Scraped new pages for trading, concepts, and API reference sections
- Updated changelog and new index pages

docs/api-reference/core/get-user-activity.md

@@ -4,13 +4,11 @@
 
 # Get user activity
 
-> Returns on-chain activity for a user.
-
 
 
 ## OpenAPI
 
-````yaml api-reference/data-api-openapi.yaml get /activity
+````yaml api-spec/data-openapi.yaml get /activity
 openapi: 3.0.3
 info:
   title: Polymarket Data API
@@ -34,7 +32,6 @@ paths:
       tags:
         - Core
       summary: Get user activity
-      description: Returns on-chain activity for a user.
       parameters:
         - in: query
           name: limit
@@ -230,4 +227,4 @@ components:
       required:
         - error
 
-````
+````