fix(clients): reject dot names and recover legacy clients (#7062)

Reject reserved dot-segment client names and recover legacy records through query aliases. Preserve token scopes and path identity precedence, and update the generated API reference.

internal/web/service/client_email_validation_test.go

@@ -7,6 +7,10 @@ func TestValidateClientEmail(t *testing.T) {
 		"alice",
 		"alice@example.com",
 		"user-123_test.name",
+		"...",
+		".alice",
+		"alice.",
+		"alice..example",
 		"имя",
 	}
 	for _, email := range valid {
@@ -16,6 +20,8 @@ func TestValidateClientEmail(t *testing.T) {
 	}
 
 	invalid := []string{
+		".",
+		"..",
 		"i6dui/",
 		"a/b",
 		"client with spaces",