fix: verify edge-owned HSTS during deployment

backend/common/test_deployment_security.py

@@ -0,0 +1,16 @@
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+
+
+def test_edge_hsts_ownership_is_explicit_and_verified():
+    settings = (ROOT / "backend/config/settings.py").read_text(encoding="utf-8")
+    deploy = (ROOT / "scripts/deploy_production.sh").read_text(encoding="utf-8")
+    workflow = (ROOT / ".gitea/workflows/deploy.yml").read_text(encoding="utf-8")
+    example = (ROOT / ".env.production.example").read_text(encoding="utf-8")
+
+    assert 'os.getenv("DJANGO_HSTS_AT_EDGE", "false")' in settings
+    assert '["security.W004"]' in settings
+    assert "DJANGO_HSTS_AT_EDGE=true" in workflow
+    assert "strict-transport-security:.*max-age=[1-9][0-9]*" in deploy
+    assert "DJANGO_HSTS_AT_EDGE=false" in example