Add ERC-4246 and pool interfaces.

contracts/PoolConfigurableSettings.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+/**
+ * @title The various configurable settings that customize Pool behavior.
+ */
+struct PoolConfigurableSettings {
+    uint256 maxCapacity;
+    uint256 poolEndDate;
+    uint256 lateFee;
+    uint256 withdrawalFee;
+    // TODO: add in Pool fees
+}

contracts/PoolLifeCycleState.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+/**
+ * @title Expresses the various states a pool can be in throughout its lifecycle.
+ */
+enum PoolLifeCycleState {
+    Initialized,
+    Active,
+    Paused,
+    Closed
+}

contracts/PoolWithdrawalPeriod.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+/**
+ * @dev Contains the start and enddate of a given withdrawal period.
+ */
+struct PoolWithdrawalPeriod {
+    uint256 start;
+    uint256 end;
+}

contracts/interfaces/IERC4246.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+/**
+ * @title The interface according to the ERC-4626 standard.
+ */
+interface IERC4626 is IERC20 {
+    /**
+     * @dev Emitted when tokens are deposited into the vault via the mint and deposit methods.
+     */
+    event Deposit(
+        address indexed caller,
+        address indexed owner,
+        uint256 assets,
+        uint256 shares
+    );
+
+    /**
+     * @dev Emitted when shares are withdrawn from the vault by a depositor in the redeem or withdraw methods.
+     */
+    event Withdraw(
+        address indexed caller,
+        address indexed receiver,
+        address indexed owner,
+        uint256 assets,
+        uint256 shares
+    );
+
+    /**
+     * @dev Return the address of the underlying ERC-20 token used for the vault for accounting, depositing, withdrawing.
+     */
+    function asset() external view returns (address);
+
+    /**
+     * @dev Calculate the total amount of underlying assets held by the vault.
+     */
+    function totalAssets() external view returns (uint256);
+
+    /**
+     * @dev Calculates the amount of shares that would be exchanged by the vault for the amount of assets provided.
+     */
+    function convertToShares(uint256 assets) external view returns (uint256);
+
+    /**
+     * @dev Calculates the amount of assets that would be exchanged by the vault for the amount of shares provided.
+     */
+    function convertToAssets(uint256 shares) external view returns (uint256);
+
+    /**
+     * @dev Calculates the maximum amount of underlying assets that can be deposited in a single deposit call by the receiver.
+     */
+    function maxDeposit(address receiver) external view returns (uint256);
+
+    /**
+     * @dev Allows users to simulate the effects of their deposit at the current block.
+     */
+    function previewDeposit(uint256 assets) external view returns (uint256);
+
+    /**
+     * @dev Deposits assets of underlying tokens into the vault and grants ownership of shares to receiver.
+     * Emits a {Deposit} event.
+     */
+    function deposit(uint256 assets, address receiver)
+        external
+        returns (uint256);
+
+    /**
+     * @dev Returns the maximum amount of shares that can be minted in a single mint call by the receiver.
+     */
+    function maxMint(address receiver) external view returns (uint256);
+
+    /**
+     * @dev Allows users to simulate the effects of their mint at the current block.
+     */
+    function previewMint(uint256 shares) external view returns (uint256);
+
+    /**
+     * @dev Mints exactly shares vault shares to receiver by depositing assets of underlying tokens.
+     * Emits a {Deposit} event.
+     */
+    function mint(uint256 shares, address receiver) external returns (uint256);
+
+    /**
+     * @dev Returns the maximum amount of underlying assets that can be withdrawn from the owner balance with a single withdraw call.
+     */
+    function maxWithdraw(address owner) external view returns (uint256);
+
+    /**
+     * @dev Simulate the effects of their withdrawal at the current block.
+     */
+    function previewWithdraw(uint256 assets) external view returns (uint256);
+
+    /**
+     * @dev Burns shares from owner and send exactly assets token from the vault to receiver.
+     * Emits a {Withdraw} event.
+     */
+    function withdraw(
+        uint256 assets,
+        address receiver,
+        address owner
+    ) external returns (uint256);
+
+    /**
+     * @dev The maximum amount of shares that can be redeemed from the owner balance through a redeem call.
+     */
+    function maxRedeem(address owner) external view returns (uint256);
+
+    /**
+     * @dev Simulates the effects of their redeemption at the current block.
+     */
+    function previewRedeem(uint256 shares) external view returns (uint256);
+
+    /**
+     * @dev Redeems a specific number of shares from owner and send assets of underlying token from the vault to receiver.
+     * Emits a {Withdraw} event.
+     */
+    function redeem(
+        uint256 shares,
+        address receiver,
+        address owner
+    ) external returns (uint256);
+}

contracts/interfaces/IPool.sol

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+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.16;
+
+import "./IERC4246.sol";
+import "../PoolLifeCycleState.sol";
+import "../PoolWithdrawalPeriod.sol";
+import "../PoolConfigurableSettings.sol";
+
+/**
+ * @title The interface for liquidity pools.
+ */
+interface IPool is IERC4626 {
+    /**
+     * @dev Emitted when the pool transitions a lifecycle state.
+     */
+    event LifeCycleStateTransition(PoolLifeCycleState state);
+
+    /**
+     * @dev Emitted when a loan is funded from the pool.
+     */
+    event LoanFunded(address indexed loan, uint256 amount);
+
+    /**
+     * @dev Emitted when a funded loan is marked as in default.
+     */
+    event LoanDefaulted(address indexed loan);
+
+    /**
+     * @dev Emitted when a funded loan matures.
+     */
+    event LoanMatured(address indexed loan);
+
+    /**
+     * @dev Emitted when first loss is supplied to the pool.
+     */
+    event FirstLossProvided(address indexed supplier, uint256 amount);
+
+    /**
+     * @dev Emitted when a withdrawal is requested.
+     */
+    event WithdrawalRequested(address indexed lender, uint256 amount);
+
+    /**
+     * @dev Emitted when pool settings are updated.
+     */
+    event PoolSettingsUpdated(PoolConfigurableSettings settings);
+
+    /**
+     * @dev Returns the current pool lifecycle state.
+     */
+    function lifeCycleState() external view returns (PoolLifeCycleState);
+
+    /**
+     * @dev The current configurable pool settings.
+     */
+    function poolSettings()
+        external
+        view
+        returns (PoolConfigurableSettings memory settings);
+
+    /**
+     * @dev The underlying liquidity asset for the pool.
+     */
+    function liquidityType() external view returns (address);
+
+    /**
+     * @dev The manager for the pool.
+     */
+    function manager() external view returns (address);
+
+    /**
+     * @dev The amount of first loss available to the pool.
+     */
+    function firstLoss() external view returns (uint256);
+
+    /**
+     * @dev Updates the pool capacity. Can only be called by the PM.
+     */
+    function updatePoolCapacity(uint256) external returns (uint256);
+
+    /**
+     * @dev Updates the pool end date. Can only be called by the PM.
+     */
+    function updatePoolEndDate(uint256) external returns (uint256);
+
+    /**
+     * @dev Returns the withdrawal fee for a given withdrawal amount at the current block.
+     */
+    function feeForWithdrawalRequest(uint256) external view returns (uint256);
+
+    /**
+     * @dev Returns the next withdrawal window, at which a withdrawal could be completed.
+     */
+    function nextWithdrawalWindow(uint256)
+        external
+        view
+        returns (PoolWithdrawalPeriod memory);
+
+    /**
+     * @dev Submits a withdrawal request, incurring a fee.
+     */
+    function requestWithdrawal(uint256) external view;
+
+    /**
+     * @dev Called by the pool manager, this transfers liquidity from the pool to a given loan.
+     */
+    function fundLoan(address) external;
+
+    /**
+     * @dev Called by the pool manager, marks a loan as in default, updating pool accounting and allowing loan
+     * collateral to be claimed.
+     */
+    function markLoanAsInDefault(address) external;
+}