fix: handle XML namespaces in DMARCParser for web.de/gmx.net compatibility

Agent-Logs-Url: https://github.com/christianlouis/dmarq/sessions/56611674-6132-435f-ab36-728464bb9157

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

backend/app/services/dmarc_parser.py

@@ -128,6 +128,14 @@ class DMARCParser:
 
         return None
 
+    @staticmethod
+    def _strip_namespace(el) -> None:
+        """Recursively remove XML namespace prefixes from element tags in-place."""
+        if "}" in el.tag:
+            el.tag = el.tag.split("}", 1)[1]
+        for child in el:
+            DMARCParser._strip_namespace(child)
+
     @staticmethod
     def _parse_metadata(root) -> dict:
         """Parse the report_metadata section of a DMARC XML report."""
@@ -216,6 +224,7 @@ class DMARCParser:
         """
         try:
             root = ET.fromstring(xml_content)
+            DMARCParser._strip_namespace(root)
 
             report = DMARCParser._parse_metadata(root)