Integrate AI Model Check for Staking Contract v2

[rainbowpuffpuff]

Staking Contract v1 is complete and the tests are passing (see PR #8).

This issue tracks the next major feature (v2), which introduces a conditional unstaking mechanism based on an AI model's verification.

Workflow:

1. A user stakes funds (e.g., 10 NEAR).
2. To receive their reward, the user must provide data (e.g., an image of their bed, phone sensor data, etc.) that indicates they are performing a desired action (e.g., preparing to go to sleep).
3. An off-chain agent, or perhaps an on-chain AI model, will process this data.
4. The agent will check for a state change based on the model's output. If the model confirms the desired outcome, the agent will trigger a state change in the contract.
5. Once the state change is confirmed, the user is permitted to unstake their funds and receive their reward.

This will require modifications to the staking contract to allow a trusted agent to control the release of funds.