Fix hardcoded RVM shebangs in bin/ stubs

bin/rails, bin/rake, and bin/setup had shebangs pointing to a specific
developer's local RVM path (/Users/dilraj/.rvm/...) which doesn't exist
in Docker containers (or anyone else's machine). Replace with the
portable #!/usr/bin/env ruby form.

This fixes the "exec bin/rails: no such file or directory" error when
running `docker compose up`.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dsomel21

bin/rails

@@ -1,4 +1,4 @@
-#!/Users/dilraj/.rvm/rubies/ruby-3.4.5/bin/ruby
+#!/usr/bin/env ruby
 # frozen_string_literal: true
 
 APP_PATH = File.expand_path('../config/application', __dir__)

bin/rake

@@ -1,4 +1,4 @@
-#!/Users/dilraj/.rvm/rubies/ruby-3.4.5/bin/ruby
+#!/usr/bin/env ruby
 # frozen_string_literal: true
 
 require_relative '../config/boot'

bin/setup

@@ -1,4 +1,4 @@
-#!/Users/dilraj/.rvm/rubies/ruby-3.4.5/bin/ruby
+#!/usr/bin/env ruby
 # frozen_string_literal: true
 
 require 'fileutils'