s3tables: add bucket name validation and fix error handling

- Add isValidBucketName validation function for [a-z0-9_-] characters
- Validate bucket name characters match ARN parsing regex
- Fix error handling in WithFilerClient closure - properly check for lookup errors
- Add error handling for json.Marshal calls (metadata and tags)
- Improve error messages and logging

weed/s3api/s3tables/utils.go

@@ -78,6 +78,13 @@ type tableMetadataInternal struct {
 
 // Utility functions
 
+// isValidBucketName validates bucket name characters
+// Bucket names must contain only lowercase letters, numbers, hyphens, and underscores
+func isValidBucketName(name string) bool {
+	pattern := regexp.MustCompile(`^[a-z0-9_-]+$`)
+	return pattern.MatchString(name)
+}
+
 // generateVersionToken generates a unique version token
 func generateVersionToken() string {
 	return fmt.Sprintf("%d", time.Now().UnixNano())