s3tables: Validate bucket name in parseBucketNameFromARN()

Enforce the same bucket name validation rules (length, characters, reserved
prefixes/suffixes) when extracting from ARN. This prevents accepting ARNs
that the system would never create and ensures consistency with
CreateTableBucket validation.

weed/s3api/s3tables/utils.go

@@ -30,7 +30,11 @@ func parseBucketNameFromARN(arn string) (string, error) {
 	if len(matches) != 2 {
 		return "", fmt.Errorf("invalid bucket ARN: %s", arn)
 	}
-	return matches[1], nil
+	bucketName := matches[1]
+	if !isValidBucketName(bucketName) {
+		return "", fmt.Errorf("invalid bucket name in ARN: %s", bucketName)
+	}
+	return bucketName, nil
 }
 
 // parseTableFromARN extracts bucket name, namespace, and table name from ARN