Modernize dependencies, fix CI, and add rubocop-gusto

[dduugg]

Summary

CI tests against Ruby 3.2, 3.3, and 4.0 via `rubyatscale/shared-config`. Several gems were incompatible with Ruby 4.0, causing `bundle install` to fail with `minitest-5.19.0 requires ruby version < 4.0`. Also fixes a nokogiri platform lockfile issue.

Follows the same approach as rubyatscale/packwerk-extensions#62.

Dependency updates:

• Remove git-sourced packwerk override from Gemfile — packwerk 3 is on RubyGems
• Update bundler to 4.0.7 (was 2.7.2)
• Update all outdated gems: activesupport 7→8.1, rubocop 1.56→1.85, sorbet/tapioca 0.5/0.11→0.6/0.17, minitest 5.19→6.0 (Ruby 4.0 compatible), code_ownership 1.34→2.1.1 (native Rust gem), tapioca 0.11→0.17.10, spoom 1.2→1.7.11, rbs 3.10→4.0.0.dev.5, parse_packwerk 0.25→0.27, packs-specification 0.0.10→0.0.11, and many more
• Run bundle lock --normalize-platforms to fix nokogiri platform lockfile warning
• Bump required_ruby_version in gemspec from >= 2.6.0 to >= 3.2
• Remove bundler ~> 2.2 and spoom 1.2.1 version pins (spoom was pinned for Ruby 2.7 compatibility)

Sorbet/Tapioca:

• Add require 'packwerk' to sorbet/tapioca/require.rb so tapioca generates a populated packwerk RBI
• Update tapioca config to exclude gems with sorbet built-in stdlib shims (base64, benchmark, bigdecimal, drb, json, logger, racc, reline, rexml, securerandom, tsort, uri)
• Regenerate all tapioca RBI files via tapioca gems --all for updated gem versions
• Regenerate rubocop and tapioca binstubs

Linting:

• Add rubocop-gusto as a development dependency and plugin in .rubocop.yml
• Add inherit_mode (merge Exclude/Include) and inherit_gem: rubocop-gusto: config/default.yml
• Autocorrect 490 offenses from rubocop-gusto; generate .rubocop_todo.yml for remaining violations
• Remove disabled Layout cops from .rubocop.yml; autocorrect 113 resulting violations
• Update TargetRubyVersion from 2.6.0 to 3.2
• Fix Sorbet type check failures caused by Sorbet/BlockMethodDefinition autocorrect converting def to define_method inside Thor no_commands and RSpec blocks; exclude those files from the cop and revert to plain def
• Resolve Sorbet/BlockMethodDefinition in cli.rb by removing the redundant no_commands do wrapper (Thor 1.x excludes private methods from CLI commands automatically)

Test fixes for updated gem APIs:

• code_ownership 2.1.1 (Rust-based): for_file now defaults to from_codeowners: true; pass from_codeowners: false in CodeOwnershipPostProcessor to use pack-based ownership lookup
• code_ownership 2.1.1: team YAML files require a github.team field to be parsed by the Rust engine
• code_ownership 2.1.1: only recognizes top-level owner: key in package.yml, not metadata.owner; update write_package_yml spec helper to write owner at top level via config hash
• code_ownership 2.1.1: remove_file_annotation! regex requires a trailing newline; fix test fixture accordingly
• Psych 5: YAML array items are no longer indented under parent key; update test expectations

Test plan

• All 115 RSpec examples pass locally
• bundle exec rubocop passes with no offenses
• bundle exec srb tc passes with no errors
• CI passes on Ruby 3.2, 3.3, and 4.0

Fixes https://github.com/rubyatscale/packs/actions/runs/22733988234

🤖 Generated with Claude Code

[dduugg]

These indentation changes are needed due to rubyatscale/parse_packwerk#47

(It would be nice to fix the indentation logic so that it remained yamllint-compatible, I'll look into that separately)