refactor: apply chef-custom-resources workflow

[damacus]

Apply the chef-custom-resources workflow across all six phases.

Changes

Phase 1: Research

• Add LIMITATIONS.md documenting platform support, architecture, Java requirements, and known incompatibilities

Phase 2: Structure

• Move test cookbook from test/fixtures/cookbooks/confluence_test/ → test/cookbooks/test/
• Update Berksfile to reference new test cookbook path
• Update kitchen.yml: provisioner chef_zero → chef_infra, run_list refs confluence_test::* → test::*, add InSpec verifier paths
• Remove EOL platforms from kitchen.global.yml (debian-11, ubuntu-20.04, opensuse-leap-15)
• Add missing oraclelinux-8 and oraclelinux-9 to CI matrix in .github/workflows/ci.yml
• Remove old ServerSpec integration tests (4 suites + helpers)
• Remove 4 stale templates (confluence.init.erb, crowd.properties.erb, response.varfile.erb, web_app.conf.erb)

Phase 3: Resources

• Add # frozen_string_literal: true to all Ruby files
• Add :delete action to confluence_service — stops, disables, and deletes the systemd unit
• Add :delete action to confluence_config — removes all 3 managed config files
• Extend :remove action on confluence_install to also remove home_path

Phase 4: ChefSpec (TDD)

• Add specs for new :delete/:remove actions (written before implementation)
• Add frozen_string_literal and documentation formatter to spec_helper.rb
• 64 examples, 0 failures

Phase 5: Integration Tests

• Replace ServerSpec with proper InSpec profiles for default and standalone suites
• Each suite has inspec.yml + controls/ with named controls per convention

Phase 6: Documentation

• Add :delete action to confluence_service.md and confluence_config.md
• Update :remove description in confluence_install.md to reflect home_path removal

[github-actions]

Slowest examples

Top 10 slowest examples (0.5 seconds, 31.83% of total time)

Example	Description	Time in seconds
spec/unit/resources/confluence_install_spec.rb:75	confluence_install with default properties creates the logs directory with correct ownership	0.0902
spec/unit/resources/confluence_install_spec.rb:75	confluence_install with default properties creates the temp directory with correct ownership	0.08269
spec/unit/resources/confluence_config_spec.rb:15	confluence_config with default properties creates confluence-init.properties	0.04753
spec/unit/resources/confluence_config_spec.rb:135	confluence_config with :delete action deletes setenv.sh	0.04539
spec/unit/resources/confluence_service_spec.rb:53	confluence_service with :stop action stops the confluence service	0.04284
spec/unit/resources/confluence_install_spec.rb:96	confluence_install with custom properties creates the custom group	0.0416
spec/unit/resources/confluence_install_spec.rb:75	confluence_install with default properties creates the work directory with correct ownership	0.04099
spec/unit/resources/confluence_install_spec.rb:100	confluence_install with custom properties creates the custom user	0.03886
spec/unit/resources/confluence_install_spec.rb:17	confluence_install with default properties creates the confluence group	0.03782
spec/unit/resources/confluence_install_spec.rb:40	confluence_install with default properties creates the home directory	0.03773