Notification upgrades: lifecycle, configurable levels, summaries

- NOTIFY_LEVELS chooses which event levels are sent (default trade,error).
- NOTIFY_LIFECYCLE sends explicit start/stop messages; the kill switch always
  notifies at error level.
- SUMMARY_INTERVAL_MINUTES sends a periodic portfolio summary (equity, per
  strategy P&L, allocation, halted state) via a background task started with
  the run and stopped on stop/kill/shutdown.
- Wires the new vars plus the go-live vars through both compose files and the
  deploy workflow. Adds tests.

README.md

@@ -191,6 +191,15 @@ best-effort: a failing channel never affects trading. For Telegram, create a bot
 with [@BotFather](https://t.me/BotFather), message it once, then read the chat id
 from `https://api.telegram.org/bot<token>/getUpdates`.
 
+Additional controls:
+
+- `NOTIFY_LEVELS` (default `trade,error`) — which event levels to send; add
+  `warning` or `info`.
+- `NOTIFY_LIFECYCLE` (default `true`) — explicit start/stop messages; the kill
+  switch always notifies.
+- `SUMMARY_INTERVAL_MINUTES` (default `0`) — periodic portfolio summary (equity,
+  per-strategy P&L and allocation).
+
 ## Adding a strategy
 
 Drop a file in `backend/app/engine/strategies/` — it is auto-discovered and