Missing pause / unpause functions prevents emergency protocol shutdown

This issue was found during the mitigation period as part of the recommended mitigation for F-2025-0004 (the max reward allocation finding).

The contract inherits from PausableUpgradeable but does not implement the necessary functions to utilise this functionality. The contract initialises the pausable functionality with __Pausable_init() but does not expose any functions to actually pause or unpause the contract.

If a critical vulnerability is discovered or if the contract needs to be temporarily halted for any reason:

1. The team cannot pause the contract to prevent further exploitation.
2. Users can continue interacting with a potentially vulnerable contract.
3. The emergency mitigation mechanism is completely non-functional.

This is particularly concerning as the pause functionality was meant to be a safety mechanism for emergency situations.

Add pause and unpause functions:

/**
 * @notice Pauses the contract, preventing staking and unstaking
 * @dev Only callable by owner
 */
function pause() public onlyOwner {
    _pause();
}

/**
 * @notice Unpauses the contract, allowing staking and unstaking
 * @dev Only callable by owner
 */
function unpause() public onlyOwner {
    _unpause();
}

Ample Protocol: Fixed.

Zealynx: Verified.