fix: migrate to Policyfile and clean up checks

[damacus]

Summary

• Replace Berksfile dependency resolution with Policyfile.rb
• Update ChefSpec and Kitchen to use Policyfile resolution
• Clean up markdownlint and Cookstyle issues exposed during migration
• Keep visualstudio Windows-path ChefSpec assertions passing under Policyfile-backed ChefSpec

Verification

• chef install Policyfile.rb
• cookstyle --no-server --cache-root /private/tmp/rubocop_cache
• markdownlint-cli2 "**/*.md"
• embedded rspec --format progress
• git diff --check

[github-actions]

Slowest examples

Top 10 slowest examples (12.98 seconds, 61.94% of total time)

Example	Description	Time in seconds
spec/install_update_spec.rb:22	visualstudio::install_update Visual Studio 2012 Ultimate Edition installs the VS 2012 update	1.74326
spec/install_spec.rb:152	visualstudio::install Windows 2012R2 customizes the AdminDeployment.xml when install_items set on the node	1.69216
spec/install_spec.rb:124	visualstudio::install Windows 2012R2 Visual Studio 2013 Ultimate installs Visual Studio 2013 Ultimate when edition and version attribute are set	1.2662
spec/install_spec.rb:74	visualstudio::install Windows 2012R2 Visual Studio 2010 specifies /q for silent installation by default	1.24057
spec/install_spec.rb:179	visualstudio::install Ubuntu 18.04 defaults the install_dir attribute correctly	1.21958
spec/install_vsto_spec.rb:23	visualstudio::install_vsto Visual Studio 2012 Ultimate Edition installs VSTO for VS 2012	1.19529
spec/install_update_spec.rb:7	visualstudio::install_update Visual Studio 2015 Community Edition does not install any updates by default	1.1735
spec/install_spec.rb:93	visualstudio::install Windows 2012R2 Visual Studio 2010 specifies /unattendfile when an unattend.ini file is given	1.15351
spec/install_spec.rb:42	visualstudio::install Windows 2012R2 Visual Studio 2012 Ultimate defaults the Visual Studio 2012 install dir to Microsoft Visual Studio 11.0	1.1513
spec/install_spec.rb:10	visualstudio::install Windows 2012R2 Visual Studio 2015 Professional installs Visual Studio 2015 Professional when only edition attribute is set	1.14643