feat: add IPackageRegistry

Author: zacksfF

src/interfaces/IPackageRegistry.sol

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+/// @title IPackageRegistry
+/// @notice Interface for EthPM v3 Package Registry based on EIP-2678
+/// @dev Defines functions for publishing and retrieving packages
+interface IPackageRegistry {
+    /// @notice Publish a package to the registry
+    /// @param name Package name (lowercase, numbers, hyphens only)
+    /// @param version Package version
+    /// @param manifestURI Content-addressable URI (e.g., ipfs://)
+    function publish(string calldata name, string calldata version, string calldata manifestURI) external;
+    
+    /// @notice Get package manifest URI
+    /// @param name Package name
+    /// @param version Package version
+    /// @return manifestURI The content-addressable URI of the package manifest
+    function getPackageURI(string calldata name, string calldata version) external view returns (string memory);
+    
+    /// @notice Check if package version exists
+    /// @param name Package name
+    /// @param version Package version
+    /// @return exists True if package exists
+    function packageExists(string calldata name, string calldata version) external view returns (bool);
+}
+