feat(snacks): add snacks_win_opts for user to override opts of Snacks.terminal.open()

[qw457812]

Case:

• Floating window.
• Toggle to show/hide the snacks terminal.

local toggle_key = "<C-,>"
return {
  {
    "coder/claudecode.nvim",
    dependencies = { "folke/snacks.nvim" },
    keys = {
      { toggle_key, "<cmd>ClaudeCodeFocus<cr>", desc = "Claude Code", mode = { "n", "x" } },
    },
    opts = {
      terminal = {
        ---@module "snacks"
        ---@type snacks.win.Config|{}
        snacks_win_opts = {
          position = "float",
          width = 0.9,
          height = 0.9,
          keys = {
            claude_hide = {
              toggle_key,
              function(self)
                self:hide()
              end,
              mode = "t",
              desc = "Hide",
            },
          },
        },
      },
    },
  },
}