`make pdf` deletes PDF output immediately

When building a PDF with `make pdf`, the script removes the output directory immediately after building the PDF; it also reports `Output can be found in ./$(DOCS_BUILDDIR)`, which is not true.

I can see how you can still use the command to test whether the PDF builds (although I would still like to see the resulting PDF).

I suggest either removing the command in its current form, documenting it to highlight that it's purely a build check, or reworking it to separate the build and cleanup functions so it can actually be used to preview PDF builds locally.

Start at the `make pdf` entry point and inspect how it builds the PDF, removes the output directory, and reports the output path. Determine the intended behavior from the issue's alternatives, then verify that the command either preserves a usable PDF or clearly documents its build-check-only behavior.

Written by the indexing model from the issue text.