Add RuboCop linting and newline enforcement

.github/workflows/lint.yml

@@ -0,0 +1,26 @@
+name: Lint
+
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+    branches: [master, main]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.0.6'
+        bundler-cache: true
+
+    - name: Run RuboCop
+      run: bundle exec rubocop
+
+    - name: Check for files missing newlines
+      run: bundle exec rake check_newlines

.github/workflows/ruby.yml

@@ -15,7 +15,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.7.6
+        ruby-version: 3.0.6
         bundler-cache: true
     - name: Run tests
       run: bundle exec rake

.rubocop.yml

@@ -0,0 +1,64 @@
+inherit_from: .rubocop_todo.yml
+
+plugins:
+  - rubocop-rake
+  - rubocop-rspec
+
+AllCops:
+  TargetRubyVersion: 3.0
+  NewCops: enable
+  Exclude:
+    - 'vendor/**/*'
+    - 'spec/fixtures/**/*'
+    - 'tmp/**/*'
+    - 'pkg/**/*'
+    - 'node_modules/**/*'
+    - 'specs_e2e/**/*'
+    - 'e2e/**/*'
+
+# Ensure all files end with a newline
+Layout/TrailingEmptyLines:
+  Enabled: true
+  EnforcedStyle: final_newline
+
+# Ensure no trailing whitespace
+Layout/TrailingWhitespace:
+  Enabled: true
+
+# Line length is configured in .rubocop_todo.yml for existing violations
+
+# Allow longer blocks in specs and rake tasks
+Metrics/BlockLength:
+  Exclude:
+    - 'spec/**/*'
+    - '**/*.rake'
+    - 'Rakefile'
+    - '*.gemspec'
+
+# Allow longer methods in rake tasks
+Metrics/MethodLength:
+  Exclude:
+    - '**/*.rake'
+    - 'Rakefile'
+
+# String literals - configured in .rubocop_todo.yml for gradual adoption
+
+# Frozen string literal pragma - configured in .rubocop_todo.yml for gradual adoption
+
+# Documentation
+Style/Documentation:
+  Enabled: false
+
+# Allow compact module/class definitions
+Style/ClassAndModuleChildren:
+  Enabled: false
+
+# RSpec specific
+RSpec/ExampleLength:
+  Max: 20
+
+RSpec/MultipleExpectations:
+  Max: 5
+
+RSpec/NestedGroups:
+  Max: 4