fix: pass max_tokens to Ollama provider in cascade router (#622)

Co-authored-by: Kimi Agent <kimi@timmy.local>
Co-committed-by: Kimi Agent <kimi@timmy.local>

src/infrastructure/router/cascade.py

@@ -564,6 +564,7 @@ class CascadeRouter:
                 messages=messages,
                 model=model or provider.get_default_model(),
                 temperature=temperature,
+                max_tokens=max_tokens,
                 content_type=content_type,
             )
         elif provider.type == "openai":
@@ -604,6 +605,7 @@ class CascadeRouter:
         messages: list[dict],
         model: str,
         temperature: float,
+        max_tokens: int | None = None,
         content_type: ContentType = ContentType.TEXT,
     ) -> dict:
         """Call Ollama API with multi-modal support."""
@@ -614,13 +616,15 @@ class CascadeRouter:
         # Transform messages for Ollama format (including images)
         transformed_messages = self._transform_messages_for_ollama(messages)
 
+        options = {"temperature": temperature}
+        if max_tokens:
+            options["num_predict"] = max_tokens
+
         payload = {
             "model": model,
             "messages": transformed_messages,
             "stream": False,
-            "options": {
-                "temperature": temperature,
-            },
+            "options": options,
         }
 
         timeout = aiohttp.ClientTimeout(total=self.config.timeout_seconds)