refactor(renderer): Separate render loop from single frame rendering

[SyedaAnshrahGillani]

This pull request refactors the CliRenderer to improve code clarity and
maintainability.

The core rendering logic has been extracted from the loop() method into a
new private method called _renderFrame().

This change allows renderOnce() to directly call the rendering logic without
invoking the entire loop, which is more efficient and semantically correct.
The loop() method now focuses on its primary responsibility: managing the
rendering loop and scheduling frames.

This refactoring improves the overall structure of the CliRenderer and makes
the code easier to understand and maintain. No functional changes are
introduced.

[kommander]

Hey, thanks for contributing! I see your concerns. I need to test this.

For me the loop() method is basically the render method, just running one cycle. Extracting that would still need to take care of the deltaTime though, should not just be 0.