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/cli.py

@@ -49,7 +49,7 @@ def _die(exc: BaseException) -> None:
     err(str(exc))
     hint = (
         "Дальше: gpu-rent status · gpu-rent logs · gpu-rent stop "
-        "(Ctrl+C на туннеле GPU не гасит)"
+        "(Ctrl+C на туннеле GPU не гасит; Ctrl+D гасит)"
     )
     msg = str(exc)
     if "gpu-rent status" not in msg and "Дальше:" not in msg:
@@ -809,7 +809,7 @@ def logs(
 def tunnel(
     open_browser: bool = typer.Option(False, "--open", help="Открыть браузер на 17801"),
 ) -> None:
-    """SSH localhost:17801 -> VM :7801. Ctrl+C закрывает туннель, GPU оставляет."""
+    """SSH localhost:17801 -> VM :7801. Ctrl+C — туннель off; Ctrl+D — stop GPU."""
     try:
         cfg = load_config(require_auth=True)
         state = load_state()
@@ -1052,7 +1052,7 @@ def resize_data(gb: int = typer.Option(..., "--gb", help="Новый разме
 
 watchdog_app = typer.Typer(
     help=(
-        "Локальный сервис: если туннель умер без Ctrl+C / stop — "
+        "Локальный сервис: если туннель умер без Ctrl+C / Ctrl+D / stop — "
         "через grace удалить compute. Не путать с idle-killer на VM."
     ),
     no_args_is_help=True,