[Documentation] Add documentation for batch 1 components

[djalmaaraujo]

Related issue

Related to #334

Description

This PR adds documentation files for the first batch of 9 components:

• Accordion - A vertically stacked set of interactive headings that each reveal a section of content
• Alert - Displays a callout for user attention (with variants: default, warning, destructive, success)
• Alert Dialog - A modal dialog that interrupts the user with important content and expects a response
• Aspect Ratio - Displays content within a desired ratio (16/9, 4/3, 1/1, 21/9)
• Avatar - An image element with a fallback for representing the user (with multiple sizes)
• Badge - Displays a badge with multiple variants and colors
• Breadcrumb - Indicates the user's current location within a navigational hierarchy
• Calendar - A date field component that allows users to enter and edit date
• Card - Displays a card with header, content, and footer

These documentation files are installed via bin/rails g ruby_ui:install:docs and allow users to see component examples and usage patterns.

Testing instructions

Execute the following tests with a Rails app that has ruby_ui installed:

1. Point your Rails app to the local ruby_ui source in Gemfile:

   gem "ruby_ui", path: "../ruby_ui"

2. If you have any existing docs files, remove them to test fresh installation:

   rm -f app/views/docs/accordion.rb
   rm -f app/views/docs/alert.rb
   rm -f app/views/docs/alert_dialog.rb
   rm -f app/views/docs/aspect_ratio.rb
   rm -f app/views/docs/avatar.rb
   rm -f app/views/docs/badge.rb
   rm -f app/views/docs/breadcrumb.rb
   rm -f app/views/docs/calendar.rb
   rm -f app/views/docs/card.rb

3. Run the docs generator:

   bin/rails g ruby_ui:install:docs

4. Verify that all docs files were created:

   • app/views/docs/accordion.rb should exist
   • app/views/docs/alert.rb should exist
   • app/views/docs/alert_dialog.rb should exist
   • app/views/docs/aspect_ratio.rb should exist
   • app/views/docs/avatar.rb should exist
   • app/views/docs/badge.rb should exist
   • app/views/docs/breadcrumb.rb should exist
   • app/views/docs/calendar.rb should exist
   • app/views/docs/card.rb should exist

5. Run tests in the ruby_ui repo:

   bundle exec rake