feat: route Mistral models natively to Mistral API and map model names correctly

backend.py

@@ -715,11 +715,19 @@ async def chat_completions(request: Request, authorization: str = Header(None)):
     stream = body.get("stream", False)
     session_id = body.get("session_id") or str(uuid.uuid4())
     
+    # Route Mistral queries natively to the Mistral API
+    client = nim_client
+    if "mistral" in requested_model.lower():
+        if mistral_client:
+            client = mistral_client
+            if requested_model == "mistralai/mistral-large-2-instruct":
+                requested_model = "mistral-large-latest"
+    
     is_agentic = requested_model in TOOL_CAPABLE_MODELS
     request_id = str(uuid.uuid4())[:8]
 
     ACTIVE_SESSIONS.add(session_id)
-    log_activity(f"Session [{session_id[:6]}] connected. Model: {requested_model}")
+    log_activity(f"Session [{session_id[:6]}] connected. Model: {requested_model} | Provider: {'Mistral' if client == mistral_client else 'NIM'}")
 
     # Build message history
     final_messages = []
@@ -760,7 +768,7 @@ async def chat_completions(request: Request, authorization: str = Header(None)):
                 kwargs["tools"] = TOOLS
                 kwargs["tool_choice"] = "auto"
             async with completions_semaphore:
-                response = await nim_client.chat.completions.create(**kwargs)
+                response = await client.chat.completions.create(**kwargs)
             content = response.choices[0].message.content or ""
             await save_message(session_id, "assistant", content)
             ACTIVE_SESSIONS.discard(session_id)
@@ -793,7 +801,7 @@ async def chat_completions(request: Request, authorization: str = Header(None)):
                     full_content = ""
                     tool_calls_raw = {}  # index -> {id, name, arguments_str}
                     
-                    async for chunk in await nim_client.chat.completions.create(**kwargs):
+                    async for chunk in await client.chat.completions.create(**kwargs):
                         choice = chunk.choices[0] if chunk.choices else None
                         if not choice:
                             continue