Add Account framework docs and guides (#5660)

contracts/mocks/docs/account/MyAccountERC7702.sol

@@ -0,0 +1,20 @@
+// contracts/MyAccountERC7702.sol
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import {Account} from "../../../account/Account.sol";
+import {ERC721Holder} from "../../../token/ERC721/utils/ERC721Holder.sol";
+import {ERC1155Holder} from "../../../token/ERC1155/utils/ERC1155Holder.sol";
+import {ERC7821} from "../../../account/extensions/draft-ERC7821.sol";
+import {SignerERC7702} from "../../../utils/cryptography/signers/SignerERC7702.sol";
+
+contract MyAccountERC7702 is Account, SignerERC7702, ERC7821, ERC721Holder, ERC1155Holder {
+    /// @dev Allows the entry point as an authorized executor.
+    function _erc7821AuthorizedExecutor(
+        address caller,
+        bytes32 mode,
+        bytes calldata executionData
+    ) internal view virtual override returns (bool) {
+        return caller == address(entryPoint()) || super._erc7821AuthorizedExecutor(caller, mode, executionData);
+    }
+}

contracts/mocks/docs/account/MyFactoryAccount.sol

@@ -0,0 +1,37 @@
+// contracts/MyFactoryAccount.sol
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {Clones} from "../../../proxy/Clones.sol";
+import {Address} from "../../../utils/Address.sol";
+
+/**
+ * @dev A factory contract to create accounts on demand.
+ */
+contract MyFactoryAccount {
+    using Clones for address;
+    using Address for address;
+
+    address private immutable _impl;
+
+    constructor(address impl_) {
+        require(impl_.code.length > 0);
+        _impl = impl_;
+    }
+
+    /// @dev Predict the address of the account
+    function predictAddress(bytes calldata callData) public view returns (address) {
+        return _impl.predictDeterministicAddress(keccak256(callData), address(this));
+    }
+
+    /// @dev Create clone accounts on demand
+    function cloneAndInitialize(bytes calldata callData) public returns (address) {
+        address predicted = predictAddress(callData);
+        if (predicted.code.length == 0) {
+            _impl.cloneDeterministic(keccak256(callData));
+            predicted.functionCall(callData);
+        }
+        return predicted;
+    }
+}