Add Docker build & GHCR publish stage, fix CI workflows, update AGENTS.md and testing docs

Agent-Logs-Url: https://github.com/christianlouis/dmarq/sessions/9d256101-34b6-4861-a8cf-7f86f32b54d5

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

backend/app/api/api_v1/endpoints/domains.py

@@ -1,6 +1,6 @@
+import random  # Used for mock data generation - TODO: Replace with actual historical data
 from datetime import datetime, timedelta
 from typing import Any, Dict, List, Optional
-import random  # Used for mock data generation - TODO: Replace with actual historical data
 
 from app.services.report_store import ReportStore
 from fastapi import APIRouter, HTTPException, Path, Query, status

backend/app/models/report.py

@@ -62,7 +62,9 @@ class ReportRecord(Base):
     count = Column(Integer, nullable=False, default=0)
 
     # Policy evaluation
-    disposition = Column(String, nullable=False)  # none, quarantine, reject (indexed via __table_args__)
+    disposition = Column(
+        String, nullable=False
+    )  # none, quarantine, reject (indexed via __table_args__)
     dkim = Column(String, nullable=True, index=True)  # pass, fail
     spf = Column(String, nullable=True, index=True)  # pass, fail
 

backend/app/models/user.py

@@ -1,8 +1,7 @@
+from app.core.database import Base
 from sqlalchemy import Boolean, Column, Integer, String
 from sqlalchemy.orm import relationship
 
-from app.core.database import Base
-
 
 class User(Base):
     """User model"""

backend/app/tests/conftest.py

@@ -1,11 +1,9 @@
-import pytest
-from app.core.database import Base, get_db
-
 # Import all models so Base.metadata knows every table
 import app.models.domain  # noqa: F401
 import app.models.report  # noqa: F401
 import app.models.user  # noqa: F401
-
+import pytest
+from app.core.database import Base, get_db
 from app.services.report_store import ReportStore
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
@@ -18,8 +16,8 @@ def test_app() -> FastAPI:
     """Create a fresh FastAPI application instance for testing."""
     from app.main import create_app
 
-    app = create_app()
-    return app
+    application = create_app()
+    return application
 
 
 @pytest.fixture()