refactor: reorder Langfuse import logic for improved clarity

Moved logger import before Langfuse block to fix NameError.

Author: anouar-bm

lightrag/llm/openai.py

@@ -10,17 +10,6 @@
 if not pm.is_installed("openai"):
     pm.install("openai")
 
-# Try to import Langfuse for LLM observability (optional)
-# Falls back to standard OpenAI client if not available
-try:
-    from langfuse.openai import AsyncOpenAI
-    LANGFUSE_ENABLED = True
-    logger.info("Langfuse observability enabled for OpenAI client")
-except ImportError:
-    from openai import AsyncOpenAI
-    LANGFUSE_ENABLED = False
-    logger.debug("Langfuse not available, using standard OpenAI client")
-
 from openai import (
     APIConnectionError,
     RateLimitError,
@@ -37,6 +26,19 @@
     safe_unicode_decode,
     logger,
 )
+
+# Try to import Langfuse for LLM observability (optional)
+# Falls back to standard OpenAI client if not available
+try:
+    from langfuse.openai import AsyncOpenAI
+
+    LANGFUSE_ENABLED = True
+    logger.info("Langfuse observability enabled for OpenAI client")
+except ImportError:
+    from openai import AsyncOpenAI
+
+    LANGFUSE_ENABLED = False
+    logger.debug("Langfuse not available, using standard OpenAI client")
 from lightrag.types import GPTKeywordExtractionFormat
 from lightrag.api import __api_version__