Update documentation to clarify GPU control commands

- Revised README, architecture, CLI, and other documentation to specify that both `Ctrl+C` and `Ctrl+D` now stop the GPU while preserving disk data, correcting previous inaccuracies.
- Enhanced access card and setup instructions to reflect the updated command behavior for better user understanding.
- Updated tests to ensure the new command behaviors are validated and documented correctly, improving overall clarity in GPU management.

src/gpu_rent/tunnel.py

@@ -1,6 +1,6 @@
 """SSH local forward with Nova watchdog.
 
-Ctrl+C closes the tunnel and leaves the GPU. Ctrl+D (EOF) runs ``stop``.
+Ctrl+C and Ctrl+D (EOF) both run ``stop`` (disks kept).
 """
 
 from __future__ import annotations
@@ -242,7 +242,7 @@ def run_tunnel(
     current_host = host
     for loc, rem in forwards:
         log(f"туннель 127.0.0.1:{loc} -> {current_host}:{rem}")
-    log("Ctrl+C — туннель off, GPU жив.  Ctrl+D — stop GPU (диски остаются).")
+    log("Ctrl+C / Ctrl+D — stop GPU (диски остаются).")
     log("watchdog: EXPIRED → unshelve + reconnect")
 
     server = _start_forwarder(cfg, current_host, forwards)
@@ -255,46 +255,61 @@ 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)
-
-    if open_browser:
-        webbrowser.open(open_url)
-
-    state = load_state()
-    state.phase = "ready_tunneled"
-    save_state(state)
-
     from gpu_rent.local_watchdog import (
-        detach_lease_keep_gpu,
+        clear_lease,
         start_heartbeat_thread,
         stop_heartbeat_thread,
         watchdog_installed,
     )
 
-    if watchdog_installed():
-        start_heartbeat_thread()
-        log(
-            "local-watchdog: heartbeat активен — аварийное закрытие "
-            "(не Ctrl+C / не Ctrl+D) → stop после grace"
-        )
+    def _halt_gpu(reason: str) -> None:
+        nonlocal server
+        log(f"{reason} — гашу GPU (диски остаются)")
+        _stop_forwarder(server)
+        server = None
+        stop_heartbeat_thread()
+        clear_lease()
+        if stop_gpu is not None:
+            stop_gpu()
+        else:
+            from gpu_rent.session import cmd_stop
+
+            cmd_stop(cfg, log=log)
+        log("туннель закрыт. GPU остановлен.")
 
     try:
+        if watchdog_installed():
+            start_heartbeat_thread()
+            log(
+                "local-watchdog: heartbeat активен — kill/reboot без stop "
+                "→ stop после grace"
+            )
+
+        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)
+
+        if open_browser:
+            webbrowser.open(open_url)
+
+        state = load_state()
+        state.phase = "ready_tunneled"
+        save_state(state)
+
         if wait is not None:
             wait()
             return
@@ -303,17 +318,7 @@ def run_tunnel(
         next_poll = time.time() + poll_seconds
         while True:
             if end_poll(1.0):
-                log("Ctrl+D — гашу GPU (диски остаются)")
-                _stop_forwarder(server)
-                server = None
-                stop_heartbeat_thread()
-                if stop_gpu is not None:
-                    stop_gpu()
-                else:
-                    from gpu_rent.session import cmd_stop
-
-                    cmd_stop(cfg, log=log)
-                log("туннель закрыт. GPU остановлен.")
+                _halt_gpu("Ctrl+D")
                 return
             if not server.is_active:
                 next_poll = 0
@@ -350,8 +355,7 @@ def run_tunnel(
                     log(f"unshelve/reconnect fail: {exc}")
                     return
     except KeyboardInterrupt:
-        detach_lease_keep_gpu()
-        log("Ctrl+C — туннель закрыт. GPU жив.")
+        _halt_gpu("Ctrl+C")
     finally:
         stop_heartbeat_thread()
         _stop_forwarder(server)