feat(gui): Add link deletion and DAG cycle validation to Visual DAG

temp_edit3.py

@@ -0,0 +1,46 @@
+with open('src/gui_2.py', 'r', encoding='utf-8', newline='') as f:
+    content = f.read()
+
+old = '''   # Handle link deletion
+   if ed.begin_delete():
+    deleted = ed.get_deleted_link()
+    if deleted:
+     link_id = deleted[0]
+     for t in self.active_tickets:
+      tid = str(t.get('id', ''))
+      for d in t.get('depends_on', []):
+       if abs(hash(d + "_" + tid)) == link_id:
+        t['depends_on'] = [dep for dep in t['depends_on'] if dep != d]
+        self._push_mma_state_update()
+        break
+    ed.end_delete()
+   ed.end()'''
+
+new = '''   # Handle link deletion
+   if ed.begin_delete():
+    deleted = ed.get_deleted_link()
+    if deleted:
+     link_id = deleted[0]
+     for t in self.active_tickets:
+      tid = str(t.get('id', ''))
+      for d in t.get('depends_on', []):
+       if abs(hash(d + "_" + tid)) == link_id:
+        t['depends_on'] = [dep for dep in t['depends_on'] if dep != d]
+        self._push_mma_state_update()
+        break
+    ed.end_delete()
+   # Validate DAG after any changes
+   try:
+    from src.dag_engine import TrackDAG
+    ticket_dicts = [{'id': str(t.get('id', '')), 'depends_on': t.get('depends_on', [])} for t in self.active_tickets]
+    temp_dag = TrackDAG(ticket_dicts)
+    if temp_dag.has_cycle():
+     imgui.open_popup("Cycle Detected!")
+   except Exception:
+    pass
+   ed.end()'''
+
+content = content.replace(old, new)
+with open('src/gui_2.py', 'w', encoding='utf-8', newline='') as f:
+    f.write(content)
+print('Done')