docs: tweak Braintrust code example reference. will be accurate as soon as temporalio/samples-python#273 is mereged'

Author: ethanruhe

docs/develop/python/integrations/braintrust.mdx

@@ -25,7 +25,7 @@ Braintrust adds the observability layer: see exactly what your agents are doing,
 The integration connects these capabilities with minimal code changes.
 Every Workflow and Activity becomes a span in Braintrust, and every LLM call is traced with inputs, outputs, tokens, and latency.
 
-All code snippets in this guide are taken from the [deep research sample](https://docs.temporal.io/ai-cookbook).
+All code snippets in this guide are taken from the [deep research sample](https://github.com/temporalio/samples-python/tree/main/braintrust).
 Refer to the sample for the complete code and run it locally.
 
 ## Prerequisites
@@ -235,7 +235,7 @@ except Exception as e:
 
 ## Example: Deep Research Agent
 
-The [deep research sample](https://docs.temporal.io/ai-cookbook) demonstrates a complete AI agent that:
+The [deep research sample](https://github.com/temporalio/samples-python/tree/main/braintrust) demonstrates a complete AI agent that:
 
 - Plans research strategies
 - Generates search queries