Sanitize /nix/store/* paths in saved .window_states[*].tabs[*].pane_tree.process.argv for vim/nvim/gvim

[andreystepanov]

This change improves session saving by sanitizing the executable path and command-line arguments (argv) for nix-wrapped Vim/Neovim executables.

• Replaces full /nix/store/... executable paths with the corresponding basename (process_info.name) to avoid unstable paths across sessions.`
• Cleans specific command flags (--cmd and -c) followed by nix store paths from process_info.argv to prevent pollution of shell history and improve session portability.
• Applies this cleanup only for known Vim-related executables (vim, nvim, gvim).
• Leaves all other arguments and executables untouched for general compatibility.
• Ensures the first element of argv is always the sanitized executable name.
• Overall results in cleaner, more stable session JSON with fewer environment-specific artifacts.

This targeted fix addresses issues with restoring nix-wrapper influenced sessions, improving usability on NixOS setups without affecting other platforms or applications.

.window_states[*].tabs[*].pane_tree.process before:

{
  "argv": [
    "/nix/store/jx332jllgyrqbnzi8svnk8xbygc9nbmp-neovim-unwrapped-0.11.5/bin/nvim",
    "--cmd",
    "lua vim.g.loaded_node_provider=0;vim.g.loaded_perl_provider=0;vim.g.loaded_python_provider=0;vim.g.python3_host_prog='/nix/store/252cmdyhmr8ai7qz266yrawgmx7nfz5h-neovim-0.11.5/bin/nvim-python3';vim.g.ruby_host_prog='/nix/store/252cmdyhmr8ai7qz266yrawgmx7nfz5h-neovim-0.11.5/bin/nvim-ruby'",
    "--cmd",
    "set packpath^=/nix/store/g0f4d93y9q79q84qq4g41lyfcw3i1z7h-vim-pack-dir",
    "--cmd",
    "set rtp^=/nix/store/g0f4d93y9q79q84qq4g41lyfcw3i1z7h-vim-pack-dir",
    "Cargo.toml"
  ],
  "cwd": "/home/user/project",
  "executable": "/nix/store/jx332jllgyrqbnzi8svnk8xbygc9nbmp-neovim-unwrapped-0.11.5/bin/nvim",
  "name": "nvim",
  "start_time": 6840603,
  "status": "Sleep"
}

.window_states[*].tabs[*].pane_tree.process after:

{
  "argv": [
    "nvim",
    "Cargo.toml"
  ],
  "cwd": "/home/user/project",
  "executable": "nvim",
  "name": "nvim",
  "start_time": 6840603,
  "status": "Sleep"
}