docs: sync Polymarket docs - 2026-04-14

docs/api-reference/trade/send-heartbeat.md

@@ -1,3 +1,7 @@
+> ## Documentation Index
+> Fetch the complete documentation index at: https://docs.polymarket.com/llms.txt
+> Use this file to discover all available pages before exploring further.
+
 # Send heartbeat
 
 > Sends a heartbeat signal to maintain active session status.
@@ -5,6 +9,9 @@ If heartbeats are not sent regularly, all open orders for the user will be autom
 This is useful for automated trading systems that need to ensure orders are canceled
 if the system becomes unresponsive.
 
+
+
+
 ## OpenAPI
 
 ````yaml /api-spec/clob-openapi.yaml post /heartbeats
@@ -130,6 +137,4 @@ components:
       name: POLY_TIMESTAMP
       description: Unix timestamp of the request
 
-````
-
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+````