Bump development local Ruby version from 3.3.1 to 3.4.8

[larouxn]

What are you trying to accomplish?

Small gem maintenance fix to bring local development Ruby up to date. Somewhat unlikely folks have Ruby 3.3.1 installed at this point, meanwhile 3.4.8 is the latest and greatest. 🚀

https://www.ruby-lang.org/en/news/2025/12/17/ruby-3-4-8-released/

Note, there are some new console warnings re: literal string freezing and no-longer-automatically-included gems. For the former it appears we need to upgrade to at least v0.10.1 of the phonelib gem, of which we're currently on v0.8.7, re: the v0.10.1 release notes. For the latter we need to add the gems (ostruct, reline, reline, irb) to our Gemfile. Will do this in a follow-up PR.

/home/larouxn/.gem/ruby/3.4.4/gems/phonelib-0.8.7/lib/phonelib/phone.rb:27: warning: literal string will be frozen in the future (run with --debug-frozen-string-literal for more information)

/home/larouxn/.gem/ruby/3.4.4/gems/phonelib-0.8.7/lib/phonelib/phone_formatter.rb:162: warning: literal string will be frozen in the future (run with --debug-frozen-string-literal for more information)

/home/larouxn/.gem/ruby/3.4.4/gems/rake-13.0.6/lib/rake.rb:33: warning: ostruct was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add ostruct to your Gemfile or gemspec to silence this warning.

/home/larouxn/.rubies/ruby-3.4.4/lib/ruby/3.4.0/readline.rb:4: warning: reline was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add reline to your Gemfile or gemspec to silence this warning.

/home/larouxn/.gem/ruby/3.4.4/gems/byebug-11.1.3/lib/byebug/commands/irb.rb:4: warning: irb was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add irb to your Gemfile or gemspec to silence this warning.

/home/larouxn/.gem/ruby/3.4.4/gems/activesupport-7.1.1/lib/active_support/logger_thread_safe_level.rb:4: warning: logger was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 3.5.0.
You can add logger to your Gemfile or gemspec to silence this warning.

What approach did you choose and why?

Standard practice.

What should reviewers focus on?

Is there any particular reason why we don't want to use latest Ruby in development? I can't think of a reason.

The impact of these changes

Better development experience especially for those coming to the repo fresh with modern Ruby.

Testing

Checklist

• I have added a CHANGELOG entry for this change (or determined that it isn't needed)

Determined not necessary as it's a developer facing change, not user facing.