docs: Add support for generating a documentation site through Doxygen.

[SharafMohamed]

Description

• Adds files for generating documentation in /docs:

  • Doxyfile
  • mainpage.dox
  • groups.dox

• Update unit tests with:

  • valid C++ names to allow doxygen to output them as functions.
  • fixed markdown syntax to improve formatting of doxygen output.
  • new docstrings for simple unit tests to improve formatting of doxygen output.

• Add doxygen workflow action to .github/workflows/docs.yaml.

• Add doxygen tasks to taskfile/docs.yaml:

  • clean to remove existing documentation and tooling
  • site to generate the documentation
  • https-server (internal) to set up a local server
  • serve to run the above 3 tasks to clean, generate, and host the documentation.

Validation performed

• Generating the site through tasks and manually through doxygen both work.
• GH workflow successfully completes.

Summary by CodeRabbit

• Documentation

  • Introduced Doxygen configuration, main page, group definitions, and example/unit test references for enhanced project documentation.
  • Added a custom compact dark theme and a toggle button for switching between light and dark modes in the generated documentation.
  • Included a persistent dark mode toggle script and a custom footer in the documentation output.

• New Features

  • Added a new test case to improve multi-line input parsing coverage, specifically handling delimiters and variable tokens across lines.

• Bug Fixes

  • Improved handling of delimiters and state transitions in multi-line parsing for more consistent token recognition.