bug: malformed line numbers when sending `{this}` to opencode

[bennylb]

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Neovim version (nvim -v)

0.11.4

Operating system/version

MacOS 15.6.1 (24G90)

Describe the bug

Making a visual selection and sending {this} with <leader>at, or <leader>ap and selecting a prompt that contains {this}, line numbers inserted to opencode's input field are malformed.

I think the line number portion :L21-L22 is missing 3 characters so appears like 1-L22.

It also appears an additional space character is being inserted before the line portion, including other cli agents (claude code, codex etc), to form @file :L21-L22.

Steps To Reproduce

1. Make a visual selection in a buffer
2. Send {this} with <leader>at or prompt with <leader>ap
3. See malformed line numbers in opencode's input field

Expected Behavior

@file:L<N>-L<M> inserted to the input field of opencode.

Repro

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

require("lazy.minit").repro({
  spec = {
    { "folke/sidekick.nvim", opts = {} },
    -- add any other plugins here
  },
})

[folke]

the problem was that we use nvim_chan_send to simulate key presses, but opencode reacts to that and shows autocomplete dialogs while still sending the text.

The solution was to use nvim_paste instead, so the result is now the same as if you were to paste the prompt in the opencode input field.