feat: detect ghostty config files by canonical path

Problem: enabled() only checked for the 'ghostty' filetype, but many
users have ghostty config files detected as 'config' or with no
filetype set. These users got no completions.

Solution: check canonical ghostty config directories
($XDG_CONFIG_HOME/ghostty, ~/.config/ghostty, /etc/ghostty) when the
filetype is 'config' or empty, resolving symlinks to handle indirect
paths.

lua/blink-cmp-ghostty.lua

@@ -10,9 +10,31 @@ function M.new()
   return setmetatable({}, { __index = M })
 end
 
+local ghostty_config_dirs = {
+  vim.fn.expand('$XDG_CONFIG_HOME/ghostty'),
+  vim.fn.expand('$HOME/.config/ghostty'),
+  '/etc/ghostty',
+}
+
 ---@return boolean
 function M.enabled()
-  return vim.bo.filetype == 'ghostty'
+  if vim.bo.filetype == 'ghostty' then
+    return true
+  end
+  if vim.bo.filetype ~= 'config' and vim.bo.filetype ~= '' then
+    return false
+  end
+  local path = vim.api.nvim_buf_get_name(0)
+  if path == '' then
+    return false
+  end
+  local real = vim.uv.fs_realpath(path) or path
+  for _, dir in ipairs(ghostty_config_dirs) do
+    if real:find(dir, 1, true) == 1 then
+      return true
+    end
+  end
+  return false
 end
 
 ---@return blink.cmp.CompletionItem[]

spec/ghostty_spec.lua

@@ -98,6 +98,43 @@ describe('blink-cmp-ghostty', function()
       helpers.delete_buffer(bufnr)
     end)
 
+    it('returns true for config filetype in ghostty config dir', function()
+      local source = require('blink-cmp-ghostty')
+      local bufnr = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_set_option_value('filetype', 'config', { buf = bufnr })
+      local config_path = vim.fn.expand('$HOME/.config/ghostty/config')
+      vim.api.nvim_buf_set_name(bufnr, config_path)
+      local original_realpath = vim.uv.fs_realpath
+      vim.uv.fs_realpath = function(p)
+        if p == config_path then
+          return config_path
+        end
+        return original_realpath(p)
+      end
+      assert.is_true(source.enabled())
+      vim.uv.fs_realpath = original_realpath
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('returns false for config filetype outside ghostty dir', function()
+      local source = require('blink-cmp-ghostty')
+      local bufnr = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_set_option_value('filetype', 'config', { buf = bufnr })
+      vim.api.nvim_buf_set_name(bufnr, '/tmp/some-other/config')
+      local original_realpath = vim.uv.fs_realpath
+      vim.uv.fs_realpath = function(p)
+        if p == '/tmp/some-other/config' then
+          return '/tmp/some-other/config'
+        end
+        return original_realpath(p)
+      end
+      assert.is_false(source.enabled())
+      vim.uv.fs_realpath = original_realpath
+      helpers.delete_buffer(bufnr)
+    end)
+
     it('returns false for other filetypes', function()
       local bufnr = helpers.create_buffer({}, 'lua')
       local source = require('blink-cmp-ghostty')