Enhance SSH configuration and security group management

- Added optional SSH security-group CIDR configuration in `env.example` to allow broader access if needed.
- Improved `guess_operator_cidr` function to support multiple IP retrieval services and allow overriding CIDR via environment variable.
- Refactored security group management to ensure idempotency and proper logging of security group rules.
- Introduced helper function `_get_volume_or_none` for better volume management and error handling.
- Updated `wait_ssh` function to enhance SSH connection handling with improved timeout settings and logging.
- Added state reset logic in `cmd_up` to handle scenarios where the server is not found in the cloud.

src/gpu_rent/session.py

@@ -155,6 +155,16 @@ def cmd_up(
                 return state
             raise CloudError(f"сервер gpu-rent в статусе {status} — разбери в панели")
 
+        if state.server_id:
+            log(f"в state был server {state.server_id}, в облаке нет — создаём заново")
+            state.server_id = None
+            state.server_name = None
+            state.floating_ip = None
+            state.floating_ip_id = None
+            state.bootstrapped = False
+            state.phase = "idle"
+            save_state(state)
+
         flavors = list(iter_flavors(conn))
         try:
             picked = resolve_flavor(