feat(pages): add roadmap page

[ReenigneArcher]

Description

Add a roadmap rendering to the website.

TODO:

• hide heading OR add a banner image
• split scripts into separate js file(s)
• split styling into css file(s)
• use common styling from index.html
  • colors
  • spacing
• markdown rendering of issue body
• possibly create a popup modal when a card is selected that shows full details
• sort labels alphabetically

Screenshot

Issues Fixed or Closed

• Closes roadmap: add roadmap page to website roadmap#62

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[Copilot]

Pull Request Overview

This PR introduces a new Roadmap page that renders GitHub issues as roadmap items with a modal for detailed issue views.

• Added roadmap.html with the page structure, banner image settings, and modal markup.
• Created assets/js/roadmap.js to dynamically fetch issues from GitHub and render them in cards, including sorting labels and parsing markdown text.
• Updated assets/js/projects.js with proper variable declarations and _config_theme.yml to add a navigation link for the Roadmap page.

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated no comments.

File	Description
roadmap.html	Adds the Roadmap page layout and modal for viewing issue details.
assets/js/roadmap.js	Implements fetching, rendering, and modal functionality for roadmap items.
assets/js/projects.js	Fixes variable declaration for the project container element.
_config_theme.yml	Inserts a new navigation link to the Roadmap page.

Files not reviewed (1)

• _sass/styles.scss: Language not supported