Fix incorrect Save As reopen after toast dismiss

[nehayadav827]

Changes

• Added flow-aware toast handling in Menu.tsx
• Prevented Save As dialog from reopening after unrelated save failures
• Preserved existing Save As validation behavior
• Added conditional reopen logic based on the originating toast flow

Testing

• Verified Save As validation flow still reopens correctly
• Verified save failure flow no longer reopens Save As dialog
• Confirmed toast dismiss behavior works correctly in both scenarios

Proof

Attached console/UI validation screenshots demonstrating:

• Save failure toast no longer reopens Save As
• Save As validation flow still behaves correctly

Issue

Fixes #86