Update documentation and CLI behavior for GPU management

- Clarified the behavior of `Ctrl+C` and `Ctrl+D` in the README and other documentation, specifying that `Ctrl+C` only stops the tunnel while keeping the GPU active, and `Ctrl+D` stops the GPU while preserving disk data.
- Enhanced the CLI documentation to reflect these changes, ensuring users understand the implications of these commands during GPU operations.
- Improved the handling of data bindings and remounting logic in the codebase to prevent issues with empty model tabs in the UI.
- Added tests to validate the new command behaviors and ensure proper documentation alignment.

src/gpu_rent/tunnel.py

@@ -1,7 +1,12 @@
-"""SSH local forward with Nova watchdog. Ctrl+C closes tunnel only."""
+"""SSH local forward with Nova watchdog.
+
+Ctrl+C closes the tunnel and leaves the GPU. Ctrl+D (EOF) runs ``stop``.
+"""
 
 from __future__ import annotations
 
+import os
+import sys
 import time
 import webbrowser
 from collections.abc import Callable
@@ -138,6 +143,57 @@ def _stop_forwarder(server) -> None:
         pass
 
 
+def poll_ctrl_d(timeout: float = 1.0) -> bool:
+    """True if the user sent Ctrl+D / EOF. Ctrl+C stays KeyboardInterrupt.
+
+    Windows console delivers Ctrl+D as ``\\x04`` (and Ctrl+Z as ``\\x1a``).
+    Those keys are ignored unless we read them — the old sleep-loop never did.
+    """
+    try:
+        if not sys.stdin.isatty():
+            if timeout > 0:
+                time.sleep(timeout)
+            return False
+    except Exception:
+        if timeout > 0:
+            time.sleep(timeout)
+        return False
+
+    if os.name == "nt":
+        try:
+            import msvcrt
+        except ImportError:
+            if timeout > 0:
+                time.sleep(timeout)
+            return False
+        deadline = time.time() + max(timeout, 0.0)
+        while True:
+            if msvcrt.kbhit():
+                ch = msvcrt.getch()
+                if ch in (b"\x00", b"\xe0") and msvcrt.kbhit():
+                    msvcrt.getch()
+                    continue
+                if ch in (b"\x04", b"\x1a"):
+                    return True
+                if ch == b"\x03":
+                    raise KeyboardInterrupt
+                continue
+            if time.time() >= deadline:
+                return False
+            time.sleep(0.05)
+
+    import select
+
+    r, _, _ = select.select([sys.stdin], [], [], max(timeout, 0.0))
+    if not r:
+        return False
+    try:
+        data = os.read(sys.stdin.fileno(), 64)
+    except OSError:
+        return False
+    return (not data) or (b"\x04" in data)
+
+
 def _recover_unshelve(cfg: Config, log: Log) -> str:
     """Unshelve EXPIRED VM, rebind FIP, wait SSH. Returns new host."""
     conn = connect(cfg)
@@ -174,6 +230,8 @@ def run_tunnel(
     log: Log = print,
     wait: Callable[[], None] | None = None,
     poll_seconds: float = 30.0,
+    stop_gpu: Callable[[], None] | None = None,
+    session_end_poll: Callable[[float], bool] | None = None,
 ) -> None:
     try:
         _ssh_tunnel_forwarder()
@@ -184,7 +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 закрывает туннель, GPU оставляет. Стоп GPU: gpu-rent stop")
+    log("Ctrl+C — туннель off, GPU жив.  Ctrl+D — stop GPU (диски остаются).")
     log("watchdog: EXPIRED → unshelve + reconnect")
 
     server = _start_forwarder(cfg, current_host, forwards)
@@ -233,7 +291,7 @@ def run_tunnel(
         start_heartbeat_thread()
         log(
             "local-watchdog: heartbeat активен — аварийное закрытие "
-            "(не Ctrl+C) → stop после grace"
+            "(не Ctrl+C / не Ctrl+D) → stop после grace"
         )
 
     try:
@@ -241,9 +299,22 @@ def run_tunnel(
             wait()
             return
 
+        end_poll = session_end_poll or poll_ctrl_d
         next_poll = time.time() + poll_seconds
         while True:
-            time.sleep(1)
+            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.")
+                return
             if not server.is_active:
                 next_poll = 0
             if time.time() < next_poll:
@@ -280,7 +351,7 @@ def run_tunnel(
                     return
     except KeyboardInterrupt:
         detach_lease_keep_gpu()
-        log("туннель закрыт. GPU жив.")
+        log("Ctrl+C — туннель закрыт. GPU жив.")
     finally:
         stop_heartbeat_thread()
         _stop_forwarder(server)