chore: import upstream snapshot with attribution

apps/backend/e2e_monitor/bundle.py

@@ -0,0 +1,50 @@
+"""Evidence-bundle directory layout + JSON helpers."""
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+
+@dataclass
+class Bundle:
+    """One run's evidence bundle under ``artifacts/e2e-monitor/<run-id>/``."""
+
+    root: Path        # artifacts/e2e-monitor
+    run_id: str
+
+    @property
+    def dir(self) -> Path:
+        return self.root / self.run_id
+
+    @property
+    def logs_dir(self) -> Path:
+        return self.dir / "logs"
+
+    @property
+    def data_dir(self) -> Path:
+        return self.dir / "data"
+
+    @property
+    def master_dir(self) -> Path:
+        return self.dir / "master"
+
+    def variation_dir(self, jd_key: str) -> Path:
+        d = self.dir / "variations" / jd_key
+        d.mkdir(parents=True, exist_ok=True)
+        return d
+
+    def ensure(self) -> None:
+        for d in (self.dir, self.logs_dir, self.data_dir, self.master_dir):
+            d.mkdir(parents=True, exist_ok=True)
+
+    @staticmethod
+    def write_json(path: Path, obj: Any) -> None:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(json.dumps(obj, ensure_ascii=False, indent=2), encoding="utf-8")
+
+    @staticmethod
+    def read_json(path: Path) -> Any:
+        return json.loads(path.read_text(encoding="utf-8"))