Emit events for transparency in main function

The sweep function, which handles unauthorized donations and extra tokens, doesn't emit an event. Consider adding an event emission for better transparency and easier off-chain tracking.

• Decreased transparency for users and auditors
• Hindered historical auditing of contract actions
• Potential difficulties in integrating with external systems

Add an event emission at the end of the sweep function. For example:

event Swept(address indexed token, uint256 amount);

function sweep(address token) external requiresAuth {
    // ... existing function body ...

    emit Swept(token, sweptAmount);
}