test: inject draft encryption key into release journey

tests/e2e/test_mobile_offline_issue_release.py

@@ -84,6 +84,9 @@ def release_server(archive: Path, tmp_path: Path, gitea_url: str):
         "STACKCHAIN_DASHBOARD_AUTH_MODE": "operator",
         "STACKCHAIN_DASHBOARD_ACCESS_TOKEN": ACCESS_TOKEN,
         "STACKCHAIN_DASHBOARD_SESSION_SECRET": "artifact-browser-independent-session-secret-863",
+        "STACKCHAIN_UNFILED_DRAFT_ENCRYPTION_KEY": (
+            "ZGRkZGRkZGRkZGRkZGRkZGRkZGRkZGRkZGRkZGRkZGQ="
+        ),
         "STACKCHAIN_DASHBOARD_PUBLIC_ORIGIN": origin,
         "STACKCHAIN_STATE_DIR": str(tmp_path / "state"),
     }