deploy notebook --static requires a requirements file it never uses #923

Problem

rsconnect deploy notebook --static requires a requirements file (or --force-generate), even though the static bundle contains only the rendered HTML and Connect never builds a Python environment for it.

$ rsconnect deploy notebook --static nb.ipynb
Error: The requirements file 'requirements.txt' does not exist in '.'.
Please create the file or specify a different file with --requirements-file.
To have the requirements file generated using pip freeze, pass --force-generate.

Reproduce (main @ 01878e8)

In a directory containing only nb.ipynb, with nbconvert and ipykernel installed in the active Python:

rsconnect deploy notebook --static nb.ipynb                     # fails as above
rsconnect deploy notebook --static --force-generate nb.ipynb    # works

With --force-generate, the deployed bundle contains only nb.html and a manifest.json with appmode: static and no python section. The generated requirements are computed and then discarded.

Cause

deploy_notebook calls resolve_requirements_file(...) and Environment.create_python_environment(...) before branching on static (main.py#L2195-L2202). The static path only needs the environment's interpreter, to run nbconvert locally.

Expected

--static doesn't require or generate a requirements file. It only needs a Python interpreter with nbconvert to render the notebook.