container: hledger-flow: lib_preprocess: bash quote given column(s)

when testing header.

container/src/hledger-flow/lib/lib_preprocess.bash

@@ -2,7 +2,7 @@
 
 # docker-finance | modern accounting for the power-user
 #
-# Copyright (C) 2021-2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+# Copyright (C) 2021-2026 Aaron Fiore (Founder, Evergreen Crypto LLC)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -66,7 +66,8 @@ function lib_preprocess::test_header()
   local _column="$1"
   local _header
   _header="$(lib_preprocess::__sanitize_header $2)"
-  [[ "$_header" =~ (^${_column}$|^${_column},|,${_column},|,${_column}$) ]] && return 0 || return 2
+  # TODO: add custom delim
+  [[ "$_header" =~ (^"${_column}"$|^"${_column}",|,"${_column}",|,"${_column}"$) ]] && return 0 || return 2
 }
 
 # Assert header in given CSV header