Switch to get_client() and SDK 3.x recommended API

Changed from low-level Langfuse() client to the recommended get_client()
approach for SDK 3.x:

- Use configure() to set API credentials
- Use get_client() to get the client instance
- Use start_as_current_span() instead of start_span()
- Use start_as_current_generation() instead of start_generation()

This is the recommended approach per Langfuse SDK 3.x docs and should
properly support update_trace(user_id=...) for user tracking.

References:
- https://langfuse.com/docs/sdk/python
- https://langfuse.com/docs/tracing-features/users

🤖 Generated with Claude Code (https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: sallyom

components/runners/claude-code-runner/wrapper.py

@@ -24,7 +24,7 @@
 
 # Langfuse for LLM observability (optional)
 try:
-    from langfuse import Langfuse
+    from langfuse import get_client, configure
     LANGFUSE_AVAILABLE = True
 except ImportError:
     LANGFUSE_AVAILABLE = False
@@ -197,41 +197,34 @@ async def _run_claude_agent_sdk(self, prompt: str):
                 langfuse_enabled = os.getenv('LANGFUSE_ENABLED', '').strip().lower() in ('1', 'true', 'yes')
                 if langfuse_enabled:
                     try:
-                        langfuse_client = Langfuse(
+                        # Configure Langfuse client (SDK 3.x recommended approach)
+                        configure(
                             public_key=os.getenv('LANGFUSE_PUBLIC_KEY'),
                             secret_key=os.getenv('LANGFUSE_SECRET_KEY'),
                             host=os.getenv('LANGFUSE_HOST')
                         )
+                        langfuse_client = get_client()
 
                         # Extract user context for observability
                         user_id = os.getenv('USER_ID', '').strip()
                         user_name = os.getenv('USER_NAME', '').strip()
 
-                        # Start a span for this session (Langfuse SDK 3.x)
-                        # Top-level span becomes the trace root
-                        # Try passing user_id in metadata AND calling update_trace()
-                        langfuse_session_span = langfuse_client.start_span(
+                        # Start a span for this session using SDK 3.x recommended API
+                        # Use start_as_current_span() with get_client()
+                        langfuse_session_span = langfuse_client.start_as_current_span(
                             name="claude_agent_session",
                             input={"prompt": prompt},
-                            user_id=user_id if user_id else None,  # Try as direct parameter
                             metadata={
                                 "session_id": self.context.session_id,
                                 "namespace": self.context.get_env('AGENTIC_SESSION_NAMESPACE', 'unknown'),
                                 "user_name": user_name if user_name else None,
-                                "user_id": user_id if user_id else None,  # Also in metadata
                             },
                         )
 
-                        # Also try update_trace() as backup
+                        # Set user_id on trace using update_trace() (SDK 3.x API)
                         if user_id:
-                            try:
-                                result = langfuse_session_span.update_trace(user_id=user_id)
-                                logging.info(f"Langfuse: update_trace() returned: {result}")
-                                logging.info(f"Langfuse: Tracking session for user {user_name} ({user_id})")
-                            except Exception as e:
-                                logging.warning(f"Failed to set user_id on trace: {e}")
-                                import traceback
-                                logging.warning(traceback.format_exc())
+                            langfuse_session_span.update_trace(user_id=user_id)
+                            logging.info(f"Langfuse: Tracking session for user {user_name} ({user_id})")
 
                         logging.info(f"Langfuse tracing enabled for session")
                     except Exception as e:
@@ -636,7 +629,7 @@ async def process_response_stream(client_obj):
                                             generation_kwargs["usage_details"] = usage_dict
                                             logging.info(f"Langfuse: Tracking generation with usage: {usage_dict}")
 
-                                    generation = langfuse_client.start_generation(**generation_kwargs)
+                                    generation = langfuse_client.start_as_current_generation(**generation_kwargs)
                                     generation.end()
                             except Exception as e:
                                 logging.debug(f"Failed to create Langfuse generation: {e}")
@@ -672,7 +665,7 @@ async def process_response_stream(client_obj):
                                 # Add Langfuse span for tool decision
                                 if langfuse_client and langfuse_session_span:
                                     try:
-                                        tool_span = langfuse_client.start_span(
+                                        tool_span = langfuse_client.start_as_current_span(
                                             name=f"tool_{tool_name}",
                                             input=tool_input,
                                             metadata={