Fix JSON parsing by stripping markdown code fences from webhook response

- Webhook returns JSON wrapped in markdown code blocks (```json...```)
- Added regex to strip code fences before json_decode()
- Resolves "Syntax error" preventing results from displaying
- Added cleaned_response to debug output for verification

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

index.php

@@ -59,7 +59,12 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
             $debugInfo['http_code'] = $httpCode;
 
             if ($httpCode >= 200 && $httpCode < 300) {
-                $result = json_decode($response, true);
+                // Strip markdown code fences if present
+                $cleanedResponse = preg_replace('/^```json\s*/s', '', $response);
+                $cleanedResponse = preg_replace('/\s*```$/s', '', $cleanedResponse);
+                $debugInfo['cleaned_response'] = $cleanedResponse;
+
+                $result = json_decode($cleanedResponse, true);
                 $debugInfo['decoded_result'] = $result;
                 $debugInfo['json_decode_error'] = json_last_error_msg();
             } else {