Update app.py

app.py

@@ -153,7 +153,7 @@ def generate_mermaid_gantt(task_order, original_names, durations=None, start_tim
     gantt = "```mermaid\ngantt\n"
     gantt += "    title Task Execution Timeline\n"
     gantt += "    dateFormat  YYYY-MM-DD HH:mm\n"
-    gantt += "    axisFormat  %a %H:%M\n"
+    gantt += "    axisFormat  %a %H:%M\n    tickInterval 30minute\n"
     gantt += "    section Tasks\n"
 
     current_dt = start_date