Neovim rework.

Consolidated modules into a single file. Added syntax files over using
treesitter.

config/nvim/lua/terminal/init.lua

@@ -1,58 +0,0 @@
-local term_buf = nil
-
-local function open_term_split()
-  vim.cmd('botright vsplit')
-  local win = vim.api.nvim_get_current_win()
-  if term_buf and vim.api.nvim_buf_is_valid(term_buf) then
-    vim.api.nvim_win_set_buf(win, term_buf)
-  else
-    vim.cmd('terminal')
-    term_buf = vim.api.nvim_get_current_buf()
-  end
-  vim.api.nvim_win_set_width(win, math.floor(vim.o.columns * 0.37))
-  vim.cmd('startinsert')
-end
-
-local function toggle_term()
-  -- Check if terminal is already visible in a window
-  for _, win in ipairs(vim.api.nvim_list_wins()) do
-    if vim.api.nvim_win_get_buf(win) == term_buf then
-      vim.api.nvim_win_close(win, false)
-      return
-    end
-  end
-  open_term_split()
-end
-
-local function open_term_fullscreen()
-  if term_buf and vim.api.nvim_buf_is_valid(term_buf) then
-    vim.api.nvim_set_current_buf(term_buf)
-  else
-    vim.cmd('terminal')
-    term_buf = vim.api.nvim_get_current_buf()
-  end
-  vim.cmd('startinsert')
-end
-
-local function prev_non_term_buf()
-  local cur = vim.api.nvim_get_current_buf()
-  local bufs = vim.fn.getbufinfo({ buflisted = 1 })
-  local candidates = {}
-  for _, info in ipairs(bufs) do
-    if info.bufnr ~= cur and vim.bo[info.bufnr].buftype ~= 'terminal' then
-      table.insert(candidates, info)
-    end
-  end
-  if #candidates == 0 then
-    print('No previous non-terminal buffer')
-    return
-  end
-  table.sort(candidates, function(a, b) return a.lastused > b.lastused end)
-  vim.api.nvim_set_current_buf(candidates[1].bufnr)
-end
-
-map('n', '<leader>l', prev_non_term_buf,    { desc = 'Go to previous non-terminal buffer' })
-map('n', '<C-j>',     toggle_term,          { desc = 'Toggle terminal split' })
-map('n', '<C-o>',     open_term_fullscreen, { desc = 'Open terminal fullscreen' })
-map('t', '<C-j>',     toggle_term,          { desc = 'Toggle terminal split' })
-map('t', '<C-o>',     prev_non_term_buf,    { desc = 'Exit terminal mode' })