Restructure: Move litellm to codai.openai.litellm

- Rename codai/litellm_backend.py to codai/openai/litellm.py
- Create codai/openai/__init__.py
- Update imports in coderai and codai/__init__.py

codai/__init__.py

@@ -16,21 +16,13 @@ from .models.parser import (
 
 from .models.templates import AgenticTemplateManager
 
-# LiteLLM backend (requires litellm package)
-try:
-    from .litellm_backend import (
-        LiteLLMBackend,
-        get_litellm_backend,
-        set_litellm_backend,
-        LITELLM_AVAILABLE,
-    )
-    _LITELLM_IMPORT_ERROR = None
-except ImportError as e:
-    _LITELLM_IMPORT_ERROR = str(e)
-    LiteLLMBackend = None
-    get_litellm_backend = None
-    set_litellm_backend = None
-    LITELLM_AVAILABLE = False
+# OpenAI-compatible backends
+from .openai.litellm import (
+    LiteLLMBackend,
+    get_litellm_backend,
+    set_litellm_backend,
+    LITELLM_AVAILABLE,
+)
 
 __all__ = [
     'ModelParserDispatcher',

codai/openai/__init__.py

+# codai.openai - OpenAI-compatible API implementations
+from .litellm import (
+    LiteLLMBackend,
+    get_litellm_backend,
+    set_litellm_backend,
+    LITELLM_AVAILABLE,
+)
+
+__all__ = [
+    'LiteLLMBackend',
+    'get_litellm_backend',
+    'set_litellm_backend',
+    'LITELLM_AVAILABLE',
+]

coderai

@@ -5175,7 +5175,7 @@ async def chat_completions(request: ChatCompletionRequest):
     
     if parser_type == 'litellm':
         # Use LiteLLM backend
-        from codai.litellm_backend import get_litellm_backend, LITELLM_AVAILABLE
+        from codai.openai.litellm import get_litellm_backend, LITELLM_AVAILABLE
         
         if not LITELLM_AVAILABLE:
             raise HTTPException(