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/services/report_store.py

@@ -155,7 +155,7 @@ class ReportStore:
             return sorted_reports[:limit]
         return sorted_reports
 
-    def get_domain_sources(self, domain: str, days: int = 30) -> List[Dict[str, Any]]:
+    def get_domain_sources(self, domain: str, _days: int = 30) -> List[Dict[str, Any]]:
         """
         Get sending sources for a domain
 
@@ -206,6 +206,6 @@ class ReportStore:
             self.domain_summary.pop(domain, None)
             self.domain_sources.pop(domain, None)
             return True
-        except Exception:
+        except Exception:  # pylint: disable=broad-exception-caught
             # If any exception occurs during deletion, return False
             return False