[GH-7352] Use GitHub Pages for Rubyzen documentation

[Stelios Frantzeskakis (steliosfran)]

What changed and why

Checklist

• Tests are added or updated for the changes
• bundle exec rspec spec/ passes locally

[GH-7352] Use GitHub Pages for Rubyzen documentation

[Copilot]

Pull request overview

Sets up YARD-based documentation for the Rubyzen gem and publishes it via GitHub Pages. Adds module-level docstrings throughout lib/rubyzen, wraps the dynamically-defined RSpec matchers in YARD @!parse blocks so they appear in the generated docs, adds a .yardopts config, and a workflow that builds and deploys docs to GitHub Pages on pushes to main. Also registers the new documentation_uri in the gemspec.

Changes:

• Add YARD module/method docstrings across lib/rubyzen/** and convert matcher comments into @!parse stubs so they're documented as methods on Rubyzen::Matchers.
• Introduce .yardopts and a Docs GitHub Actions workflow that builds YARD output and deploys it to GitHub Pages.
• Wire up documentation_uri in rubyzen-lint.gemspec and add webrick to the development Gemfile group (needed for yard server).

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
rubyzen-lint.gemspec	Adds documentation_uri metadata pointing at GitHub Pages site.
lib/rubyzen/version.rb	Adds YARD docstring on VERSION.
lib/rubyzen/providers/blocks_provider.rb	Adds module-level docstring on Providers.
lib/rubyzen/parsers/a_s_t_parser.rb	Adds module-level docstring on Parsers.
lib/rubyzen/matchers/zen_true_matcher.rb	Replaces top-level comment with @!parse block exposing zen_true as a documented method.
lib/rubyzen/matchers/zen_false_matcher.rb	Same treatment for zen_false (drops the "custom failure message" example).
lib/rubyzen/matchers/zen_empty_matcher.rb	Same treatment for zen_empty (swaps "custom message" example for a baseline example).
lib/rubyzen/matchers/matcher_helpers.rb	Adds module docstring on Matchers and @!method directive describing message_for_failure.
lib/rubyzen/declarations/file_declaration.rb	Adds module-level docstring on Declarations.
lib/rubyzen/collections/base_collection.rb	Adds module-level docstring on Collections.
lib/rubyzen/cache/parse_cache.rb	Adds module-level docstring on Cache.
Gemfile	Adds webrick dev dependency for yard server.
.yardopts	New YARD config: output dir, markdown markup, included files.
.github/workflows/docs.yml	New workflow building YARD and deploying to GitHub Pages on main.