Rework 2d rendering

[kimkulling]

Summary by CodeRabbit

• New Features

  • Enhanced 2D canvas rendering with a new constructor supporting signed rectangle dimensions.
  • Debug text rendering now uses a dedicated 2D canvas renderer for improved efficiency and management.

• Bug Fixes

  • Corrected typos in method names, debug messages, and enum values.
  • Fixed mouse cursor type spelling in the progress reporter.

• Refactor

  • Standardized variable naming conventions for OpenGL-related structures and throughout the rendering backend.
  • Updated code to use signed rectangles (Rect2i) for window and viewport dimensions across the application.
  • Modernized namespace declarations and improved code style for clarity and consistency.

• Documentation

  • Improved code comments and documentation for better clarity and accuracy.