fix(mail): support LuaJIT unpack

lua/mail.lua

@@ -74,11 +74,14 @@ end
 
 km("<leader>m", "", "Mail")
 
+-- NeoMutt's Neovim Lua runtime may be LuaJIT/Lua 5.1, which exposes only global unpack.
+local unpack_args = table.unpack or unpack
+
 -- Safe wrapper: pcall so the keymap degrades gracefully if plugin not yet downloaded.
 local function nav(fn, ...)
   local args = { ... }
   local ok, nav_mod = pcall(require, "nvim-mail.navigate")
-  if ok then nav_mod[fn](table.unpack(args)) end
+  if ok then nav_mod[fn](unpack_args(args)) end
 end
 
 km("<leader>mt", function() nav("goto_field", "^[Tt]o:", "A") end, "Mail: To:")