feat: add characters validation rule

Author: ns-vasilev

Sources/ValidatorCore/Classes/Rules/CharactersValidationRule.swift

@@ -0,0 +1,33 @@
+//
+// Validator
+// Copyright © 2025 Space Code. All rights reserved.
+//
+
+import Foundation
+
+/// A characters validation rule.
+public struct CharactersValidationRule: IValidationRule {
+    // MARK: Types
+
+    public typealias Input = String
+
+    // MARK: Properties
+
+    public let characterSet: CharacterSet
+
+    /// The validation error.
+    public let error: IValidationError
+
+    // MARK: Initialization
+
+    public init(characterSet: CharacterSet, error: IValidationError) {
+        self.characterSet = characterSet
+        self.error = error
+    }
+
+    // MARK: IValidationRule
+
+    public func validate(input: String) -> Bool {
+        input.rangeOfCharacter(from: characterSet.inverted) == .none
+    }
+}