Fix pylint warnings: logging, globals, exceptions, imports, duplicates

Agent-Logs-Url: https://github.com/christianlouis/dmarq/sessions/576427d4-4f6a-46d2-b75f-6862ecbcf526

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

backend/app/tests/test_security.py

@@ -4,6 +4,7 @@ Security-focused tests for DMARQ application.
 Covers API key management, domain validation, file upload limits, and XML parsing security.
 """
 
+import app.services.dmarc_parser as parser_module
 import pytest
 from app.core.security import add_api_key, generate_api_key, verify_api_key
 from app.services.dmarc_parser import DMARCParser
@@ -123,8 +124,6 @@ class TestXMLParsingSecurity:
     """Test XML parsing security (defusedxml, XXE protection)."""
 
     def test_defusedxml_is_used(self):
-        import app.services.dmarc_parser as parser_module
-
         assert hasattr(parser_module, "ET")
         module_info = str(getattr(parser_module.ET, "__name__", "")) + str(
             getattr(parser_module.ET, "__module__", "")
@@ -149,5 +148,5 @@ class TestXMLParsingSecurity:
             result = DMARCParser.parse_file(xxe_payload, "test.xml")
             org_name = result.get("org_name", "")
             assert "root:" not in org_name and "/bin" not in org_name
-        except Exception:
+        except Exception:  # pylint: disable=broad-exception-caught
             pass  # Expected – defusedxml blocks DTD processing