refactor(vscode): reimplement terminal integration and unify calls to extension API (#6076)

## Description

This PR proposes the following changes to the VS Code extra:
- Re-implement the VS Code terminal integration (broken since
[`2f46974`](2f4697443c (diff-f878104b5415a79ed4bb9036974722cad911327fdd46994e04f5065ff90e9a55)),
see comment referenced below)
- Unify calls to the [extension
API](https://github.com/vscode-neovim/vscode-neovim/tree/v1.18.21?tab=readme-ov-file#%EF%B8%8F-api)
- Fully adopt the Lua API in favour of the deprecated Vim script
functions (see [deprecation
notice](https://github.com/vscode-neovim/vscode-neovim/tree/v1.18.21?tab=readme-ov-file#vimscript))
  - Centralise `require("vscode")` calls

## Related Issue(s)

- Fixes
https://github.com/LazyVim/LazyVim/pull/4392#issuecomment-2881395017

## Checklist

- [x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

---------

Co-authored-by: Folke Lemaitre <folke.lemaitre@gmail.com>

lua/lazyvim/plugins/extras/vscode.lua

@@ -23,6 +23,7 @@ local enabled = {
 }
 
 local Config = require("lazy.core.config")
+local vscode = require("vscode")
 Config.options.checker.enabled = false
 Config.options.change_detection.enabled = false
 Config.options.defaults.cond = function(plugin)
@@ -36,19 +37,30 @@ vim.api.nvim_create_autocmd("User", {
   callback = function()
     -- VSCode-specific keymaps for search and navigation
     vim.keymap.set("n", "<leader><space>", "<cmd>Find<cr>")
-    vim.keymap.set("n", "<leader>/", [[<cmd>lua require('vscode').action('workbench.action.findInFiles')<cr>]])
-    vim.keymap.set("n", "<leader>ss", [[<cmd>lua require('vscode').action('workbench.action.gotoSymbol')<cr>]])
+    vim.keymap.set("n", "<leader>/", function()
+      vscode.call("workbench.action.findInFiles")
+    end)
+    vim.keymap.set("n", "<leader>ss", function()
+      vscode.call("workbench.action.gotoSymbol")
+    end)
+
+    -- Toggle VS Code integrated terminal
+    for _, lhs in ipairs({ "<leader>ft", "<leader>fT", "<c-/>" }) do
+      vim.keymap.set("n", lhs, function()
+        vscode.call("workbench.action.terminal.toggleTerminal")
+      end)
+    end
 
     -- Navigate VSCode tabs like lazyvim buffers
-    vim.keymap.set("n", "<S-h>", "<Cmd>call VSCodeNotify('workbench.action.previousEditor')<CR>")
-    vim.keymap.set("n", "<S-l>", "<Cmd>call VSCodeNotify('workbench.action.nextEditor')<CR>")
+    vim.keymap.set("n", "<S-h>", function()
+      vscode.call("workbench.action.previousEditor")
+    end)
+    vim.keymap.set("n", "<S-l>", function()
+      vscode.call("workbench.action.nextEditor")
+    end)
   end,
 })
 
-function LazyVim.terminal()
-  require("vscode").action("workbench.action.terminal.toggleTerminal")
-end
-
 return {
   {
     "snacks.nvim",