feat(ui): implement premium beige design system and ux refinements

backend/app/llm.py

@@ -31,6 +31,16 @@ def create_llm(settings: Settings) -> BaseChatModel:
             api_key=settings.openai_api_key,
         )
 
+    if provider == "azure_openai":
+        from langchain_openai import AzureChatOpenAI
+
+        return AzureChatOpenAI(
+            azure_deployment=settings.azure_openai_deployment,
+            azure_endpoint=settings.azure_openai_endpoint,
+            api_key=settings.azure_openai_api_key,
+            api_version=settings.azure_openai_api_version,
+        )
+
     if provider == "google":
         from langchain_google_genai import ChatGoogleGenerativeAI
 
@@ -39,4 +49,7 @@ def create_llm(settings: Settings) -> BaseChatModel:
             google_api_key=settings.google_api_key,
         )
 
-    raise ValueError(f"Unknown LLM provider: '{provider}'. Use 'anthropic', 'openai', or 'google'.")
+    raise ValueError(
+        f"Unknown LLM provider: '{provider}'. "
+        "Use 'anthropic', 'openai', 'azure_openai', or 'google'."
+    )