folding: remove fold gutter column and related config

Author: codemedic

after/plugin/options.lua

@@ -15,39 +15,27 @@ vim.opt.guicursor = table.concat({
   'r-cr-o:hor20-blinkwait700-blinkoff200-blinkon800',
 }, ',')
 
--- Folding — treesitter-based, with modern open/close icons in the gutter
+-- Folding — treesitter-based, no gutter column
 vim.o.foldmethod = 'expr'
 vim.o.foldexpr = 'v:lua.vim.treesitter.foldexpr()'
 vim.o.foldenable = true
-vim.o.foldcolumn = '3'   -- wide enough to show fold tree without digit fallback
+vim.o.foldcolumn = '0'
 vim.o.foldlevel = 99      -- default: open everything (overridden per filetype)
 vim.o.foldlevelstart = 99 -- same for new buffers
-vim.opt.fillchars:append({
-  foldopen  = vim.fn.nr2char(0xf078), -- nf-fa-chevron-down  (open fold)
-  foldclose = vim.fn.nr2char(0xf054), -- nf-fa-chevron-right (closed fold)
-  foldsep   = '│',
-  fold      = ' ',
-})
 
--- Per-filetype fold overrides. Filetypes with deep nesting need a wider
--- foldcolumn to avoid digit fallback; foldminlines avoids noisy short folds.
----@type table<string, { foldcolumn?: string, foldminlines?: integer }>
+-- Per-filetype fold overrides.
+---@type table<string, { foldminlines?: integer }>
 local fold_ft = {
-  php        = { foldcolumn = '5' },
-  typescript = { foldcolumn = '5' },
-  javascript = { foldcolumn = '5' },
-  lua        = { foldcolumn = '4' },
-  sh         = { foldminlines = 10 },
-  bash       = { foldminlines = 10 },
+  sh   = { foldminlines = 10 },
+  bash = { foldminlines = 10 },
 }
-local fold_ft_defaults = { foldcolumn = '3', foldminlines = 10 }
+local fold_ft_defaults = { foldminlines = 1 }
 
 -- Treesitter attaches asynchronously on FileType. vim.schedule defers until
 -- after attachment, then resets foldmethod to force fold recomputation.
 vim.api.nvim_create_autocmd('FileType', {
   callback = function(args)
     local cfg = vim.tbl_extend('force', fold_ft_defaults, fold_ft[args.match] or {})
-    vim.opt_local.foldcolumn  = cfg.foldcolumn
     vim.opt_local.foldminlines = cfg.foldminlines
     vim.schedule(function()
       if pcall(vim.treesitter.get_parser, 0) then
@@ -57,13 +45,6 @@ vim.api.nvim_create_autocmd('FileType', {
   end,
 })
 
--- Match fold column markers to line number colour.
-local function link_foldcolumn()
-  vim.api.nvim_set_hl(0, 'FoldColumn', { link = 'LineNr' })
-end
-link_foldcolumn()
-vim.api.nvim_create_autocmd('ColorScheme', { callback = link_foldcolumn })
-
 -- When nvim is invoked with +N (e.g. nvim file.txt +1234), open the fold at
 -- the cursor so the target line is immediately visible. VimEnter fires after
 -- the +line command has positioned the cursor, so zv ("view cursor line")