feat: rename gem to semaphore-sms-ruby

[frinsdev]

Summary

• Rename the RubyGems package from ruby-semaphore to semaphore-sms-ruby
• Rename the public namespace from Semaphore to SemaphoreSMS (e.g. SemaphoreSMS::Client)
• Update authorship, README, and lib/spec paths to match

Why

Semaphore / ruby-semaphore is too generic and easy to confuse with other projects. The new names make it clear this gem is the Ruby client for Semaphore SMS.

Migration

# Gemfile
gem "semaphore-sms-ruby"

# Code
client = SemaphoreSMS::Client.new(...)
SemaphoreSMS.configure { |config| ... }