fix: guard preg_match from integer input in UUID7 validation

preg_match expects string but Sequence now accepts int|string. Add
is_string check so integer values skip regex and fall through to
Range validation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: abnegate

src/Database/Validator/Sequence.php

@@ -47,7 +47,7 @@ public function isValid($value): bool
 
         switch ($this->idAttributeType) {
             case Database::VAR_UUID7:
-                if (preg_match('/^[a-f0-9]{8}-[a-f0-9]{4}-7[a-f0-9]{3}-[89ab][a-f0-9]{3}-[a-f0-9]{12}$/i', $value) === 1) {
+                if (\is_string($value) && preg_match('/^[a-f0-9]{8}-[a-f0-9]{4}-7[a-f0-9]{3}-[89ab][a-f0-9]{3}-[a-f0-9]{12}$/i', $value) === 1) {
                     return true;
                 }
                 // Also accept integer IDs (e.g. $tenant may be an integer in any adapter)