feat: Snap scrolling for guides

[g123k]

Better than words, a video:
https://github.com/openfoodfacts/smooth-app/assets/246838/ff3c3a31-8d8f-4b62-acaa-2980382932f6

Or in plain text, if we scroll within the header, it will automatically scroll at the beginning/end (depending on the position).

This PR also includes all custom ScrollPhysics from the new design.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0.59880% with 166 lines in your changes are missing coverage. Please review.

Project coverage is 8.10%. Comparing base (4d9c7fc) to head (d0b712a).
Report is 132 commits behind head on develop.

Files	Patch %	Lines
packages/smooth_app/lib/helpers/physics.dart	0.00%	137 Missing ⚠️
...h_app/lib/pages/guides/helpers/guides_content.dart	3.33%	29 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #5283      +/-   ##
==========================================
- Coverage     9.54%   8.10%   -1.45%     
==========================================
  Files          325     357      +32     
  Lines        16411   18113    +1702     
==========================================
- Hits          1567    1468      -99     
- Misses       14844   16645    +1801     

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[g123k]

And now with the bouncing scroll on iOS
https://github.com/openfoodfacts/smooth-app/assets/246838/91475aaa-83d6-4185-8307-1fcf5da1a777