Resolve linter contradictions: consolidate config, fix isort first-party, pylint 10/10

Agent-Logs-Url: https://github.com/christianlouis/dmarq/sessions/1e4a1f06-55b9-4040-853e-6aaf9ee574c8

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

backend/app/tests/conftest.py

@@ -1,16 +1,17 @@
 # Import all models so Base.metadata knows every table
-import app.models.domain  # noqa: F401  # pylint: disable=unused-import
-import app.models.report  # noqa: F401  # pylint: disable=unused-import
-import app.models.user  # noqa: F401  # pylint: disable=unused-import
 import pytest
-from app.core.database import Base, get_db
-from app.main import create_app
-from app.services.report_store import ReportStore
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
+import app.models.domain  # noqa: F401  # pylint: disable=unused-import
+import app.models.report  # noqa: F401  # pylint: disable=unused-import
+import app.models.user  # noqa: F401  # pylint: disable=unused-import
+from app.core.database import Base, get_db
+from app.main import create_app
+from app.services.report_store import ReportStore
+
 
 @pytest.fixture()
 def test_app() -> FastAPI:

backend/app/tests/test_dmarc_parser.py

@@ -2,6 +2,7 @@ import io
 import zipfile
 
 import pytest
+
 from app.services.dmarc_parser import DMARCParser
 from app.tests.test_data import SAMPLE_XML
 

backend/app/tests/test_models.py

@@ -1,6 +1,7 @@
+from sqlalchemy.orm import Session
+
 from app.models.domain import Domain
 from app.models.report import DMARCReport, ReportRecord
-from sqlalchemy.orm import Session
 
 
 class TestDomainModel:

backend/app/tests/test_reports_api.py

@@ -1,9 +1,10 @@
 import io
 import zipfile
 
-from app.tests.test_data import SAMPLE_XML
 from fastapi.testclient import TestClient
 
+from app.tests.test_data import SAMPLE_XML
+
 
 def _make_zip(xml_content: str) -> bytes:
     """Create a ZIP file containing the given XML content."""

backend/app/tests/test_security.py

@@ -4,8 +4,9 @@ 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
+
+import app.services.dmarc_parser as parser_module
 from app.core.security import add_api_key, generate_api_key, verify_api_key
 from app.services.dmarc_parser import DMARCParser
 from app.utils.domain_validator import validate_domain, validate_domain_config