Create a new function to get HL plots from a PKNCAdata object

[Gero1999]

Issue

Closes #931

Description

• Added get_halflife_plots to generate Plotly-based half-life plots from PKNCA data, including fit lines, scatter points, and customizable annotations. Handles missing/excluded data robustly and supports grouping.
• Introduced internal helper get_halflife_plots_single to encapsulate the logic for rendering a single plot, managing marker colors, shapes, and hover text for individual data points.
• Added a comprehensive test suite (test-get_halflife_plots.R) covering:
  • Basic valid output and type checking.
  • Edge cases such as empty data or missing exclusion columns.
  • Correct rendering of marker colors and shapes under various inclusion/exclusion scenarios.

Definition of Done

• new fun can take as input a PKNCAdata
• new fun count with tests

How to test

No need to open the App. Just check the code logic and the tests. Run the testing file with the example input. Feel free to try with any other PKNCAdata input (although this is just optional homework 😉 )

Contributor checklist

• Code passes lintr checks
• Code passes all unit tests
• New logic covered by unit tests
• New logic is documented
• App or package changes are reflected in NEWS
• Package version is incremented
• R script works with the new implementation (if applicable)

Notes to reviewer

Tidyverse style is not followed in this PR

[js3110]

Looks good! Some nitpicks and a couple of comments/questions

[Gero1999]

Tidyverse style will be ignored for this case (PKNCA), the rest of points will be addressed

[js3110]

Tidyverse style will be ignored for this case (PKNCA), the rest of points will be addressed

What do you mean by this? I am assuming you have plans to integrate this as a PKNCA function and that PKNCA doesn't use tidyverse?

[js3110]

Nice, thanks!

[Shaakon35]

LGTM