- Add proper file descriptor cleanup for RTP capture files
- Track file ownership to avoid unlinking user-provided files
- Always close files when done, only unlink files we own
- Always setup at_exit cleanup for proper file descriptor hygiene
- Improve socket closure with proper error handling
- Fix Timeout method call (was missing Timeout. prefix)
- Convert all RSpec tests from :should to :expect syntax
- Add CLAUDE.md documentation for future development

Resolves critical file descriptor leak in /tmp/rtp_capture.raw* files
that was consuming thousands of file descriptors per process.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

- Update RuboCop to latest version in Gemfile
- Modernize Rakefile with updated task configuration
- Update gemspec with current Ruby version requirements
- Update test configuration in spec_helper
- Update Cucumber step definitions

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Production systems showing 91,900+ leaked rtp_capture.raw Tempfiles!

- Replace at_exit hook with ObjectSpace finalizer for Tempfile cleanup
- Ensures Tempfiles are closed/unlinked when Receiver objects are garbage collected
- Prevents FD exhaustion when Receiver objects are not explicitly stopped
- Process ulimit of 1024 was being exceeded causing 'Too many open files' errors

Root cause: Each RTP::Receiver created a Tempfile but only cleaned it up
at process exit. When tens of thousands of Receiver objects were created
during normal operation, all Tempfiles remained open until process exit.

This change allows the GC to clean up FDs immediately when Receiver
objects become unreachable, preventing catastrophic FD exhaustion.