make rcm usable as a gem from any directory, fix bugs and tests

- Add lib/rcm.rb entry point and bin/rcm CLI executable
- Update gemspec: v0.1.0, proper files list, executables, runtime deps
- Support standalone arg parsing and --hosts filtering in options
- Fix inverted logic and typo in FileBackup#different? (== vs !=, cecksum_b)
- Fix unqualified File.directory? resolving to RCM::File in Directory
- Fix test_chown assertions running before evaluate! creates files
- Add setup to file tests to prevent order-dependent failures

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

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/dslkeywords/given.rb b/lib/dslkeywords/given.rb
index fa14e68..ba61703 100644
--- a/lib/dslkeywords/given.rb
+++ b/lib/dslkeywords/given.rb
@@ -17,6 +17,10 @@ module RCM
     def met?
       return false if @conds.key?(:hostname) && Socket.gethostname != @conds[:hostname].to_s
 
+      # When --hosts is specified, only run on the listed hosts
+      hosts = option(:hosts)
+      return false if hosts.any? && !hosts.include?(Socket.gethostname)
+
       true
     end
   end