Implement balance monitoring and notification for Selectel API integration

- Added support for balance tracking using `SELECTEL_API_TOKEN` in the configuration.
- Introduced new balance notification logic in the local watchdog, alerting users on balance changes based on defined thresholds.
- Updated documentation to include instructions for setting up balance notifications and the required environment variables.
- Enhanced the `ready` and `session` modules to initialize balance state and handle notifications during GPU operations.
- Refactored the CLI and related components to support the new balance monitoring features, ensuring a seamless user experience.

src/gpu_rent/tunnel.py

@@ -194,6 +194,20 @@ def run_tunnel(
     else:
         open_url = f"http://127.0.0.1:{cfg.swarmui_local_port}"
 
+    from gpu_rent.ready import verify_stack_local
+
+    try:
+        local_checks = verify_stack_local(cfg, log, timeout=90.0)
+        state = load_state()
+        state.notes = dict(state.notes or {})
+        state.notes["stack_local"] = [
+            {"name": c.name, "ok": c.ok, "detail": c.detail} for c in local_checks
+        ]
+        save_state(state)
+    except CloudError as exc:
+        log(f"проверка туннеля: {exc}")
+        raise
+
     from gpu_rent.access_card import print_access_card
 
     print_access_card(cfg, tunneled=True, host=current_host)