fix: accept integer values in Sequence validator for $tenant VAR_ID type

SQL adapters return integer tenant values from getTenant(), but the
Sequence validator only accepted strings. Cast int to string before
validation to support both SQL (integer) and MongoDB (UUID string) tenants.

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

Author: abnegate

src/Database/Validator/Sequence.php

@@ -41,6 +41,10 @@ public function isValid($value): bool
             return false;
         }
 
+        if (\is_int($value)) {
+            $value = (string) $value;
+        }
+
         if (!\is_string($value)) {
             return false;
         }