Fix reasoning trace parsing for incomplete XML tags

- Update detectReasoningTrace to require both opening AND closing tags
- Add console warning when incomplete reasoning traces are detected
- Skip malformed reasoning traces to avoid confusing partial content
- Maintains full functionality for well-formed reasoning traces

js/reasoning-parser.js

@@ -12,15 +12,18 @@ class ReasoningParser {
     static detectReasoningTrace(text) {
         if (!text || typeof text !== 'string') return false;
         
-        // Check for common reasoning trace patterns
-        const patterns = [
-            /<think>/i,
-            /<thinking>/i,
-            /<reasoning>/i,
-            /<thought>/i
+        // Check for complete reasoning trace patterns (both opening and closing tags)
+        const completePatterns = [
+            { start: /<think>/i, end: /<\/think>/i },
+            { start: /<thinking>/i, end: /<\/thinking>/i },
+            { start: /<reasoning>/i, end: /<\/reasoning>/i },
+            { start: /<thought>/i, end: /<\/thought>/i }
         ];
         
-        return patterns.some(pattern => pattern.test(text));
+        // Only return true if we find BOTH opening and closing tags
+        return completePatterns.some(pattern => 
+            pattern.start.test(text) && pattern.end.test(text)
+        );
     }
     
     /**
@@ -77,6 +80,12 @@ class ReasoningParser {
             }
         }
         
+        // Check if there are incomplete reasoning tags (opening but no closing)
+        const hasOpeningTag = /<think>|<thinking>|<reasoning>|<thought>/i.test(text);
+        if (hasOpeningTag) {
+            console.warn('Incomplete reasoning trace detected - missing closing tags');
+        }
+        
         // If no patterns match, return original text as answer
         return {
             reasoning: null,