mcp(docs[lifecycle]): mark respawn argv shape as stopgap

Hand-rolled ``pane.cmd("respawn-pane", *argv)`` exists because
``libtmux>=0.55.1`` ships no ``Pane.respawn()`` yet — the wrapper
lives on libtmux's ``tmux-parity`` branch and uses the same flag
ordering this code mirrors (``-k``, ``-c``, optional trailing shell).
The inline note tells future-you that the swap, when ``Pane.respawn``
lands on the release line, is a few lines: drop the argv builder, call
``pane.respawn(kill=, start_directory=, shell=)``, drop the stderr
branch (``Pane.respawn`` raises ``LibTmuxException``). Without the
comment a reader would assume oversight.

Author: tony

src/libtmux_mcp/tools/pane_tools/lifecycle.py

@@ -153,6 +153,13 @@ def respawn_pane(
             "Use a manual tmux command if intended."
         )
         raise ToolError(msg)
+    # Stopgap: ``libtmux>=0.55.1`` has no ``Pane.respawn()`` yet — the
+    # wrapper exists on the upstream ``tmux-parity`` branch (see
+    # ``libtmux/pane.py:respawn``) and mirrors this argv shape (``-k``,
+    # ``-c <dir>``, optional trailing shell). When the release line picks
+    # it up, swap ``pane.cmd("respawn-pane", *argv)`` for ``pane.respawn(
+    # kill=kill, start_directory=start_directory, shell=shell)`` and drop
+    # the stderr branch — ``Pane.respawn`` raises ``LibTmuxException``.
     argv: list[str] = []
     if kill:
         argv.append("-k")