feat: make orchestrator contracts pausable

[matteoettam09]

We should integrate OpenZeppelin’s Pausable contract into the system.

This enables an off-chain monitor to pause the protocol when invariants are being violated. Particularly useful for detecting and mitigating non-atomic, multi-transaction exploits.

Motivation

• Many attacks occur across multiple transactions (non-atomic), giving external monitors time to detect anomalies.
• By importing:

  import { Pausable } from "@openzeppelin/contracts/utils/Pausable.sol";

we can empower an off-chain agent to pause the system quickly if invariants appear to be breaking.
Pausing helps protect funds and halts state-changing operations until investigation or remediation.

Proposed Implementation

• Inherit Pausable in core protocol contracts.
• Guard critical state-changing functions with whenNotPaused.
• Provide a restricted pause() method controlled by an authorized off-chain agent or guardian role.

References

• OpenZeppelin Pausable Docs: https://docs.openzeppelin.com/contracts/5.x/api/utils#pausable