Show confirmation dialog when user disables simulation mode in SimulationModeToggle

[Kingsman-99]

Description

Disabling simulation mode causes all subsequent actions to submit real on-chain transactions. SimulationModeToggle currently switches off immediately without warning. A confirmation dialog ("You are switching to live mode — all actions will use real funds") prevents accidental real-money transactions.

Acceptance Criteria

• Toggling simulation mode OFF opens a confirmation dialog with a clear warning message
• The toggle only flips after the user clicks "Yes, switch to live mode"
• Cancelling the dialog leaves simulation mode enabled
• Toggling simulation mode ON (back to simulation) does not require confirmation
• Existing tests continue to pass

Context

• Target file: src/components/SimulationModeToggle.tsx