feat(validators): add composite validators

Implement AllOf and AnyOf for combining multiple checks into
composite validation rules.

src/veritext/validators/composite.py

@@ -0,0 +1,90 @@
+"""Composite validators for combining multiple checks."""
+
+from veritext.core.types import CheckResult, ValidationContext, ValidationResult
+from veritext.validators.base import Check
+
+
+class AllOf:
+    """Passes only if all checks pass."""
+
+    def __init__(self, checks: list[Check]) -> None:
+        """
+        Initialise the AllOf composite validator.
+
+        Args:
+            checks: List of checks that must all pass.
+
+        Raises:
+            ValueError: If checks list is empty.
+        """
+        if not checks:
+            raise ValueError("checks list cannot be empty")
+
+        self._checks = checks
+
+    @property
+    def name(self) -> str:
+        """Return the name of this composite check."""
+        return "all_of"
+
+    def check(self, text: str, context: ValidationContext) -> ValidationResult:
+        """
+        Run all checks and return aggregate result.
+
+        Args:
+            text: The text to validate.
+            context: Validation context containing reference text and metadata.
+
+        Returns:
+            ValidationResult that passes only if all checks pass.
+        """
+        results: list[CheckResult] = []
+        for check in self._checks:
+            results.append(check.check(text, context))
+
+        all_passed = all(r.passed for r in results)
+
+        return ValidationResult(passed=all_passed, checks=results)
+
+
+class AnyOf:
+    """Passes if any check passes."""
+
+    def __init__(self, checks: list[Check]) -> None:
+        """
+        Initialise the AnyOf composite validator.
+
+        Args:
+            checks: List of checks where at least one must pass.
+
+        Raises:
+            ValueError: If checks list is empty.
+        """
+        if not checks:
+            raise ValueError("checks list cannot be empty")
+
+        self._checks = checks
+
+    @property
+    def name(self) -> str:
+        """Return the name of this composite check."""
+        return "any_of"
+
+    def check(self, text: str, context: ValidationContext) -> ValidationResult:
+        """
+        Run all checks and return aggregate result.
+
+        Args:
+            text: The text to validate.
+            context: Validation context containing reference text and metadata.
+
+        Returns:
+            ValidationResult that passes if any check passes.
+        """
+        results: list[CheckResult] = []
+        for check in self._checks:
+            results.append(check.check(text, context))
+
+        any_passed = any(r.passed for r in results)
+
+        return ValidationResult(passed=any_passed, checks=results)