Fix Mistral API parameter naming issue

- Change maxTokens to max_tokens for Mistral API compatibility
- Extract maxTokens from options before spreading to avoid parameter conflicts
- Tested successfully with live API calls

backend/src/services/mistralClient.js

@@ -50,6 +50,8 @@ Output format: JSON with fields {proposal, justification, confidence (0-1), depe
  * Call Mistral AI API
  */
 async function callMistralAPI(messages, options = {}) {
+  const { maxTokens, ...otherOptions } = options;
+
   const response = await fetch(MISTRAL_API_URL, {
     method: 'POST',
     headers: {
@@ -60,8 +62,8 @@ async function callMistralAPI(messages, options = {}) {
       model: options.model || 'mistral-small-latest',
       messages,
       temperature: options.temperature || 0.7,
-      max_tokens: options.maxTokens || 2048,
-      ...options
+      max_tokens: maxTokens || 2048,
+      ...otherOptions
     })
   });