Upgrade to Ruby 4

Author: zetter-rpf

.tool-versions

@@ -1 +1 @@
-ruby 3.4.8
+ruby 4.0.4

AGENTS.md

@@ -34,7 +34,7 @@ docker compose up
 - Full suite: `docker compose run --rm api rspec`
 - Single spec: `docker compose run --rm api rspec spec/path/to/spec.rb`
 - Lint: `docker compose run --rm api bundle exec rubocop`
-- CI: GitHub Actions with Ruby 3.4, Postgres 12, Redis.
+- CI: GitHub Actions with Ruby 4, Postgres 12, Redis.
 
 ## Where to Look First
 - Routes: `config/routes.rb`. Auth: `config/initializers/omniauth.rb`, `app/helpers/authentication_helper.rb`, `app/controllers/concerns/identifiable.rb`.

Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:3.4.8-slim-trixie AS base
+FROM ruby:4.0.4-slim-trixie AS base
 RUN gem install bundler \
   && apt-get update \
   && apt-get upgrade --yes \

Gemfile.lock

@@ -183,6 +183,7 @@ GEM
       logger
     faraday-net_http (3.4.2)
       net-http (~> 0.5)
+    ffi (1.17.2)
     ffi (1.17.2-aarch64-linux-gnu)
     ffi (1.17.2-arm64-darwin)
     ffi (1.17.2-x86_64-linux-gnu)
@@ -643,7 +644,7 @@ DEPENDENCIES
   webmock
 
 RUBY VERSION
-  ruby 3.4.8
+  ruby 4.0.4
 
 BUNDLED WITH
   4.0.10