doc: check repoducibility for same pkg version

[dagousket]

why?

• check whether Baptiste differences found in high res contrast are gone after pkg update
• resume difference at higher numerical resolution

what?

• add vignette to contrast new output from baptiste and thinkr at high resolution
• run contrast for 1e-4 and 1e-6 tolerance

issue #53

Checklist:

• [x] Does the package check works locally?
• [x] Does the CI pass?
• [x] Are the added / fixed features documented, tested?
• [x] Are the changes related to tickets / issues that I have listed in the commits and in the PR itself?
• [x] Are the tickets in "review" mode in the Project Tracking Board?
• [x] Does each ticket, if it is to be closed after acceptance of the PR, contain a comment that tells how to validate it?

[codecov[bot]]

Codecov Report

Merging #57 (a528c3f) into main (aaad3c6) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #57   +/-   ##
=======================================
  Coverage   64.43%   64.43%           
=======================================
  Files           4        4           
  Lines         537      537           
=======================================
  Hits          346      346           
  Misses        191      191           

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