Add package data for GPU rent and update CLI documentation

- Added package data configuration for the 'gpu_rent' package in pyproject.toml.
- Updated README.md to include usage instructions for Windows and Unix launchers.
- Enhanced CLI documentation in cli.md to reflect new commands and their functionalities.
- Revised setup.md to clarify installation steps and environment setup.
- Improved error handling and command descriptions in the CLI implementation.
- Added new functions for model version handling and flavor resolution in the codebase.
- Updated state management to include additional properties for better tracking.

src/gpu_rent/lock.py

@@ -0,0 +1,59 @@
+"""Single-instance lock for up/stop."""
+
+from __future__ import annotations
+
+import os
+import sys
+from types import TracebackType
+
+from gpu_rent.errors import GpuRentError
+from gpu_rent.paths import lock_path
+
+
+def _pid_alive(pid: int) -> bool:
+    if pid <= 0:
+        return False
+    if sys.platform == "win32":
+        import ctypes
+
+        handle = ctypes.windll.kernel32.OpenProcess(0x100000, False, pid)
+        if handle:
+            ctypes.windll.kernel32.CloseHandle(handle)
+            return True
+        return False
+    try:
+        os.kill(pid, 0)
+        return True
+    except OSError:
+        return False
+
+
+class SessionLock:
+    def __enter__(self) -> SessionLock:
+        path = lock_path()
+        path.parent.mkdir(parents=True, exist_ok=True)
+        if path.is_file():
+            try:
+                old = int(path.read_text(encoding="utf-8").strip() or "0")
+            except ValueError:
+                old = 0
+            if _pid_alive(old) and old != os.getpid():
+                raise GpuRentError(
+                    f"gpu-rent уже работает (pid {old}, {path}). Дождись окончания up/stop."
+                )
+        path.write_text(str(os.getpid()), encoding="utf-8")
+        self._path = path
+        self._pid = os.getpid()
+        return self
+
+    def __exit__(
+        self,
+        exc_type: type[BaseException] | None,
+        exc: BaseException | None,
+        tb: TracebackType | None,
+    ) -> None:
+        try:
+            if self._path.is_file() and self._path.read_text(encoding="utf-8").strip() == str(self._pid):
+                self._path.unlink()
+        except OSError:
+            pass