feat: add foreign key constraints and metrics for blockchain node

packages/solidity/aitbc-token/contracts/AITokenRegistry.sol

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.24;
+
+import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
+
+/// @title AITokenRegistry
+/// @notice Tracks permitted providers and staking requirements for AIToken minting
+contract AITokenRegistry is AccessControl {
+    bytes32 public constant COORDINATOR_ROLE = keccak256("COORDINATOR_ROLE");
+
+    struct ProviderInfo {
+        bool active;
+        uint256 collateral;
+    }
+
+    mapping(address => ProviderInfo) public providers;
+
+    event ProviderRegistered(address indexed provider, uint256 collateral);
+    event ProviderUpdated(address indexed provider, bool active, uint256 collateral);
+
+    constructor(address admin) {
+        _grantRole(DEFAULT_ADMIN_ROLE, admin);
+    }
+
+    function registerProvider(address provider, uint256 collateral) external onlyRole(COORDINATOR_ROLE) {
+        require(provider != address(0), "invalid provider");
+        require(!providers[provider].active, "already registered");
+        providers[provider] = ProviderInfo({active: true, collateral: collateral});
+        emit ProviderRegistered(provider, collateral);
+    }
+
+    function updateProvider(
+        address provider,
+        bool active,
+        uint256 collateral
+    ) external onlyRole(COORDINATOR_ROLE) {
+        require(provider != address(0), "invalid provider");
+        require(providers[provider].active || active, "provider not registered");
+        providers[provider] = ProviderInfo({active: active, collateral: collateral});
+        emit ProviderUpdated(provider, active, collateral);
+    }
+
+    function providerInfo(address provider) external view returns (ProviderInfo memory) {
+        return providers[provider];
+    }
+}