enabled coloured underlines for spelling diagnostics

lua/paper-tonic-modern/groups/treesitter.lua

@@ -292,6 +292,6 @@ return {
   ['@none'] = {},
   ['@conceal'] = { fg = c.fg_weaker },
   
-  ['@spell'] = {},
-  ['@nospell'] = {},
+  -- @spell and @nospell should not define any styling
+  -- This allows vim.wo.spell to control spell highlighting via SpellBad/SpellCap/etc
 }

lua/settings.lua

@@ -60,6 +60,9 @@ vim.opt.hlsearch = true -- Highlight all search matches
 vim.opt.iskeyword:append("$")
 vim.opt.iskeyword:append("-")
 
+-- Terminal and color support
+vim.opt.termguicolors = true -- Enable 24-bit RGB color (required for colored underlines)
+
 -- Visuals
 vim.opt.showbreak = "  ↳"
 vim.opt.listchars = {