👀 Safe preview: Open notebooks without running

[fonsp]

After this PR, you can open a notebook without running it! You can even make edits (change code, add/delete cells) that are saved to the file.

When you Shift+Enter, cells still won't run: you need to click the big "Start notebook", and then it will be as if you just started the notebook in old Pluto: Pkg initializes and all cells will run.

Schermopname.2023-09-19.om.15.27.12.mov

Implement #259

TODO

• Open notebook without running
• Also disable Pkg instantiate/etc without permission
• New Pkg popup message
• Check all Dynamic.jl entry points
• See changes when editing md-only cells
• Make it more clear that you need to run the notebook
• Move warning when opening from url to the run button
• Opening a URL, then closing the session, then starting the session does not show a warning.
• Configuration to disable warning (for binder etc)
• Should the notebook stay in your session? Maybe reword the "shutdown?" prompt in the main menu.
  • Keep the prompt because you are used to press enter.
• What happens when you add/remove packages while waiting for permission?
  • Adding packages works
  • If you add Pkg.activate() statically, then start the notebook, you immediately get a "Restart required"
  • If you remove a package import statically, then start the notebook, you immediately get a "Restart recommended" message
• Remove old config run_notebook_on_load or rename to run_all_cells_on_start or sth
• Tests
• Fix existing tests
• Disable scripts (and more? maybe sanitize HTML)
• Switch to DOMPurify: Fix #233 mozilla/sanitizer-polyfill#234 (comment)
• "Start notebook in background" no longer working
• Test notebookupload
• Test modifying in Safe mode
• Test fallback samples
• Test "start notebook in background" for risky source
• What should happen to the "run in background" buttons?
• Make cells with hidden code more visible.

FUTURE TODO

• From URL: offer to run with Binder/JuliaHub instead?
• Review: walk through all non-md cells one by one?
• Try to preserve the cell order that was used in the saved file?

[github-actions]

Try this Pull Request!

Open Julia and type:

julia> import Pkg
julia> Pkg.activate(temp=true)
julia> Pkg.add(url="https://github.com/fonsp/Pluto.jl", rev="wait-to-run")
julia> using Pluto

[fonsp]

Opening a notebook from a URL:

Schermopname.2023-05-18.om.14.05.32.mov

[BioTurboNick]

This feature looks great! A little encouragement to finish it, and also offer help if possible :-)