Implement init/deinit of inotify system

Use RAII to handle inotify resource lifetime, i.e. initialize with actor
creation and deinitialize with actor deletion.

Sources/Inotify/InotifyError.swift

@@ -0,0 +1,19 @@
+import CInotify
+
+public enum InotifyError: Error, Sendable, CustomStringConvertible {
+	case initFailed(errno: Int32)
+
+	public var description: String {
+		switch self {
+		case .initFailed(let code):
+			"inotify_init1 failed: \(readableErrno(code))"
+		}
+	}
+
+	private func readableErrno(_ code: Int32) -> String {
+		if let cStr = get_error_message() {
+			return String(cString: cStr) + " (errno \(code))"
+		}
+		return "errno \(code)"
+	}
+}