docs: backfill env template and migration notes for M2

tools/soak/scoreboard.py

@@ -48,6 +48,7 @@ def inv_call_ids_unique(rows: list[Row]) -> None:
 def _minute_bucket(created_at: str) -> int:
     return int(datetime.fromisoformat(str(created_at)).timestamp()) // 60
 
+
 def inv_rpm_never_exceeded(rows: list[Row], per_source_rpm: dict[str, int]) -> None:
     """不变量 3: 按遥测时间戳重算,任一分钟桶内单源请求数 ≤ RPM 配置。
 
@@ -59,9 +60,7 @@ def inv_rpm_never_exceeded(rows: list[Row], per_source_rpm: dict[str, int]) -> N
         for r in rows
         if per_source_rpm.get(r["source_name"], 0) > 0
     )
-    breaches = {
-        key: n for key, n in buckets.items() if n > per_source_rpm[key[0]]
-    }
+    breaches = {key: n for key, n in buckets.items() if n > per_source_rpm[key[0]]}
     assert not breaches, f"RPM 击穿: {dict(list(breaches.items())[:5])}"