Use ARGV like other ruby post-processing scripts

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

chatgpt-subset-feather-icon.rb

@@ -4,8 +4,8 @@
 require 'nokogiri'
 require 'set'
 
-# 1) Find all HTML files, excluding those in "venv/"
-files = Dir.glob("**/*.html").reject { |f| f.start_with?("venv") }
+# 1) Process all files passed in from the command line
+files = ARGV
 
 # 2) Extract used Feather icons
 used_icons = Set.new