fix : replaced alert call with toast notification in Dashboard.jsx

[tmdeveloper007]

Summary of What Has Been Done

Replaced the browser alert() call in the routine duplication error handler with a toast notification, following the existing inline Toast component pattern.

Changes Made

• Added useRef and useCallback imports
• Added inline Toast component for non-blocking notifications
• Added toast state and showToast helper with 3-second auto-dismiss
• Replaced alert("Failed to duplicate routine") with showToast(..., "error")
• Added Toast component to the JSX return

Impact it Made

• Non-blocking UX during routine duplication failures
• Consistent with toast notification pattern across the app

Closes #1958

Note: please assign this PR to the tmdeveloper007 account.