feat: add crew context tracking for LLM guardrail events (#3111)

Add crew context tracking using OpenTelemetry baggage for thread-safe propagation. Context is set during kickoff and cleaned up in finally block. Added thread safety tests with mocked agent execution.

src/crewai/utilities/events/llm_guardrail_events.py

@@ -1,3 +1,4 @@
+from inspect import getsource
 from typing import Any, Callable, Optional, Union
 
 from crewai.utilities.events.base_events import BaseEvent
@@ -16,23 +17,26 @@ class LLMGuardrailStartedEvent(BaseEvent):
     retry_count: int
 
     def __init__(self, **data):
-        from inspect import getsource
-
         from crewai.tasks.llm_guardrail import LLMGuardrail
         from crewai.tasks.hallucination_guardrail import HallucinationGuardrail
 
         super().__init__(**data)
 
-        if isinstance(self.guardrail, LLMGuardrail) or isinstance(
-            self.guardrail, HallucinationGuardrail
-        ):
+        if isinstance(self.guardrail, (LLMGuardrail, HallucinationGuardrail)):
             self.guardrail = self.guardrail.description.strip()
         elif isinstance(self.guardrail, Callable):
             self.guardrail = getsource(self.guardrail).strip()
 
 
 class LLMGuardrailCompletedEvent(BaseEvent):
-    """Event emitted when a guardrail task completes"""
+    """Event emitted when a guardrail task completes
+
+    Attributes:
+        success: Whether the guardrail validation passed
+        result: The validation result
+        error: Error message if validation failed
+        retry_count: The number of times the guardrail has been retried
+    """
 
     type: str = "llm_guardrail_completed"
     success: bool