Add comprehensive tests for new policy fields and combinations

Introduce tests to validate functionality for new policy fields, including `max_expiry_duration`, `protected_required`, `identifier_regex`, and `follows_whitelist_admins`. Also, cover combinations of new and existing fields to ensure compatibility and precedence rules are correctly enforced.

bump to v0.31.2

pkg/policy/kind_whitelist_test.go

@@ -121,7 +121,7 @@ func TestKindWhitelistComprehensive(t *testing.T) {
 
 	t.Run("Implicit Whitelist (rules) - kind NO rule", func(t *testing.T) {
 		policy := &P{
-			DefaultPolicy: "allow",
+			// DefaultPolicy not set (empty) - uses implicit whitelist when rules exist
 			// No explicit whitelist
 			rules: map[int]Rule{
 				1: {Description: "Rule for kind 1"},