Updated sanitization

app.py

@@ -38,8 +38,10 @@ app = gr.Server(title="Code-to-Flowchart Generator")
 
 # This is a cleaning function to resolve common syntax errors.
 def quote_labels(text: str) -> str:
-    # Mermaid node labels can't hold raw code char, so quote-wrap each label body.
-    END = r'(?=\s*(?:--|==|-\.|<|\||;|$))'
+    # Mermaid node labels can't hold raw code characters, so quote-wrap each label body
+    # A label's real closing bracket is followed by a Mermaid connector, edge-label, pipe, statement end, or EOL
+    # operators after a subscript (== < <= > >= != %) are never mistaken for a close.
+    END = r'(?=\s*(?:[-<][-.>xo]|==[>=xo]|\||;|$))'
 
     def esc(body: str) -> str:
         return (body.replace('"', "'")