Added logging the mermaid syntax to console so we can see what is actually happening.

app.py

@@ -203,6 +203,10 @@ index_html = """
                 const result = await client.predict("/generate_flowchart", { src_code: codeValue });
                 const mermaidSyntax = result.data[0];
 
+                // TEMP DIAGNOSTIC: log the exact string sent to Mermaid so parse
+                // errors can be reproduced from the raw output. Remove once resolved.
+                console.log("RAW MERMAID >>>\n" + mermaidSyntax + "\n<<< END");
+
                 // Inject the raw string into a clean layout block and re-trigger parsing
                 targetDiv.innerHTML = `<pre class="mermaid">${mermaidSyntax}</pre>`;
                 await mermaid.run();