chore(rebase): Fix conflict-resolution regressions

why: The rebase onto current master left an orphaned pre-engine code
block and stale variable names in Server.raise_if_dead, plus an unused
formats import.

what:
- Use the resolved tmux binary in the CalledProcessError command
- Drop the unreachable subprocess.check_call block orphaned inside
  _build_server_args
- Remove the unused libtmux.formats import

Author: tony

docs/pytest-plugin/index.md

@@ -0,0 +1,65 @@
+---
+myst:
+  html_meta:
+    description: "libtmux pytest plugin for testing tmux applications with pytest"
+    keywords: "tmux, pytest, plugin, testing, libtmux"
+---
+
+(pytest_plugin)=
+
+# tmux `pytest` plugin
+
+```{toctree}
+:hidden:
+:maxdepth: 2
+
+getting-started
+fixtures
+usage-examples
+advanced-techniques
+```
+
+libtmux provides pytest fixtures for tmux, making it easy to test tmux-related functionality with complete isolation. The plugin automatically manages setup and teardown of independent tmux servers, sessions, windows, and panes.
+
+```{admonition} Connect with us!
+:class: seealso
+
+Do you want more flexibility? Correctness? Power? Defaults changed? [Connect with us](https://github.com/tmux-python/libtmux/discussions) on the tracker. We want to know your use case and won't stabilize APIs until we're sure everything is by the book.
+```
+
+## Benefits at a glance
+
+- **Isolated Testing Environment**: Each test gets a fresh tmux server that won't interfere with other tests
+- **Automatic Cleanup**: Servers, sessions, and other resources are automatically cleaned up after tests
+- **Simplified Setup**: Common fixtures for server, session, window, and pane management
+- **Reliable Testing**: Consistent environment for reproducible test results
+- **Custom Configuration**: Easily test with different tmux configurations and settings
+
+## Quick installation
+
+Install `libtmux` via the Python package manager of your choice:
+
+```{code-block} console
+$ pip install libtmux
+```
+
+The pytest plugin will be automatically detected by pytest, and the fixtures will be available in your test environment.
+
+## See real-world examples
+
+View libtmux's own [tests/](https://github.com/tmux-python/libtmux/tree/master/tests) as well as tmuxp's [tests/](https://github.com/tmux-python/tmuxp/tree/master/tests) for real-world examples.
+
+For detailed code examples and usage patterns, refer to the {ref}`usage-examples` page.
+
+## Module reference
+
+```{module} libtmux.pytest_plugin
+```
+
+```{eval-rst}
+.. automodule:: libtmux.pytest_plugin
+    :members:
+    :inherited-members:
+    :private-members:
+    :show-inheritance:
+    :member-order: bysource

src/libtmux/server.py

@@ -16,7 +16,7 @@
 import typing as t
 import warnings
 
-from libtmux import exc, formats
+from libtmux import exc
 from libtmux._internal.engines.base import ServerContext
 from libtmux._internal.engines.subprocess_engine import SubprocessEngine
 from libtmux._internal.env import socket_path_from_env
@@ -362,7 +362,7 @@ def raise_if_dead(self) -> None:
         if proc.returncode is not None and proc.returncode != 0:
             raise subprocess.CalledProcessError(
                 returncode=proc.returncode,
-                cmd=[tmux_bin, *server_args, "list-sessions"],
+                cmd=[resolved, *server_args, "list-sessions"],
             )
 
     #
@@ -379,11 +379,6 @@ def _build_server_args(self) -> list[str]:
             server_args.append(f"-f{self.config_file}")
         return server_args
 
-        try:
-            subprocess.check_call([resolved, *cmd_args])
-        except FileNotFoundError:
-            raise exc.TmuxCommandNotFound from None
-
     def _probe_server(self) -> int:
         """Check server liveness without bootstrapping control mode."""
         tmux_bin = shutil.which("tmux")