fix: extract JSON from mixed debug output in workflow

When DEBUG_MODE is enabled, the workflow captures both debug output
(stderr) and JSON output (stdout) together. This caused JSON parsing
to fail because it tried to parse the entire mixed output.

Now the workflow extracts just the JSON object from the mixed output
before attempting to parse it.

Author: LearningCircuit

.github/workflows/ai-code-reviewer.yml

@@ -76,8 +76,29 @@ jobs:
             exit 1
           fi
 
+          # Extract only the JSON part (find the last valid JSON object in output)
+          # This handles debug output being mixed with the JSON response
+          # Try to find JSON by looking for lines starting with { and ending with }
+          AI_JSON=$(echo "$AI_RESPONSE" | awk '/^{$/,/^}$/{print}' | tail -n +1)
+
+          # If that didn't work, try extracting just the last line that looks like JSON
+          if [ -z "$AI_JSON" ] || ! echo "$AI_JSON" | jq . >/dev/null 2>&1; then
+            # Try to extract the last complete JSON object using perl
+            AI_JSON=$(echo "$AI_RESPONSE" | perl -0777 -ne 'print $1 if /(\{(?:[^{}]|(?R))*\})[^\{]*$/s' | tail -c 1000000)
+          fi
+
+          if [ -z "$AI_JSON" ]; then
+            echo "⚠️ Could not extract JSON from AI response."
+            if [ "$DEBUG_MODE" = "true" ]; then
+              echo "=== DEBUG: Full response (first 3000 chars) ==="
+              echo "$AI_RESPONSE" | head -c 3000
+              echo "=== END DEBUG ==="
+            fi
+            exit 1
+          fi
+
           # Parse JSON response
-          if ! echo "$AI_RESPONSE" | jq . >/dev/null 2>&1; then
+          if ! echo "$AI_JSON" | jq . >/dev/null 2>&1; then
             echo "⚠️ AI response is not valid JSON. Cannot process review."
 
             # Log raw response for debugging (redact sensitive info)
@@ -103,9 +124,9 @@ jobs:
           fi
 
           # Extract fields from JSON
-          REVIEW=$(echo "$AI_RESPONSE" | jq -r '.review // "No review provided"')
-          DECISION=$(echo "$AI_RESPONSE" | jq -r '.fail_pass_workflow // "uncertain"')
-          LABELS=$(echo "$AI_RESPONSE" | jq -r '.labels_added[]? // empty')
+          REVIEW=$(echo "$AI_JSON" | jq -r '.review // "No review provided"')
+          DECISION=$(echo "$AI_JSON" | jq -r '.fail_pass_workflow // "uncertain"')
+          LABELS=$(echo "$AI_JSON" | jq -r '.labels_added[]? // empty')
 
           # Post the review as PR comment
           echo "$REVIEW" | gh pr comment ${{ github.event.pull_request.number }} --repo ${{ github.repository }} -F -