Hide context menus on form and list pages to prevent exploits

[aldro61]

Summary

• Adds MutationObservers to remove right-click context menus on form and list pages
• On forms, the context menu provided options (like "Configure", "Export", etc.) that could be used to modify form fields outside the intended task scope
• On lists, the context menu provided options (like "Show Matching", "Filter Out", "Assign to me", etc.) that could be used to modify list data outside the intended task scope
• This prevents agents from exploiting context menus to bypass field/data restrictions

Test plan

• Right-click on a form header and verify the context menu does not appear
• Right-click on a list row and verify the context menu does not appear
• Verify form tasks still work correctly (create/edit records)
• Verify list tasks still work correctly

🤖 Generated with Claude Code