feature: expose terminal management for plugin integrations

[GeorgesAlkhouri]

Did you check the docs?

• I have read all the snacks.nvim docs

Is your feature request related to a problem? Please describe.

Hi!
I'm creating my first Neovim plugin (nvim-aider) for Aider integration. Currently, I need to reimplement terminal management logic that already exists in snacks.nvim. Access to the internal terminals table and terminal ID generation would allow better integration and reduce code duplication.

Describe the solution you'd like

Expose two internal components from snacks.terminal:

The terminals table storing active terminal instances
The terminal ID generation logic (either as a function or by exposing the implementation)

This would enable plugins to:

Track existing terminals without reimplementation
Generate consistent terminal IDs
Better integrate with snacks.nvim terminal management

Describe alternatives you've considered

I'm currently reimplementing this functionality in nvim-aider as shown in the terminal.lua module. Having access to snacks' internal terminal management would make the integration more robust and maintainable. Also many thanks for the creating of snacks.

Additional context

No response

[folke]

See the updated docs.

--- Get or create a terminal window.
--- The terminal id is based on the `cmd`, `cwd`, `env` and `vim.v.count1` options.
--- `opts.create` defaults to `true`.
---@param cmd? string | string[]
---@param opts? snacks.terminal.Opts| {create?: boolean}
---@return snacks.win? terminal, boolean? created
function M.get(cmd, opts)