Add snail pet

[WoofWoof0]

Hi there, I want to contribute to this repo by adding a new feature (pet snail). This is my first open-source PR, let me know if there is any problem, perhaps some guidance would be nice too. :)

[tonybaloney]

Please can you rename the GIFs so that they are all lower case. If you're using Windows you need to use the git mv command.

[tonybaloney]

This is a great PR, please can you look at my comments. Also please add an attribution for the artwork to README along with the others.

[tonybaloney]

Ah the snails are named incorrectly.

The file names should match the npm run test:gifs output

File "./media/snail/brown_idle_8fps.gif" does not exist.
File "./media/snail/brown_run_8fps.gif" does not exist.
File "./media/snail/brown_swipe_8fps.gif" does not exist.
File "./media/snail/brown_walk_8fps.gif" does not exist.
File "./media/snail/brown_walk_fast_8fps.gif" does not exist.
File "./media/snail/brown_with_ball_8fps.gif" does not exist.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 38.46154% with 8 lines in your changes missing coverage. Please review.

Project coverage is 17.06%. Comparing base (61374a6) to head (441977d).
Report is 28 commits behind head on main.

Files	Patch %	Lines
src/panel/pets/snail.ts	50.00%	4 Missing ⚠️
src/extension/extension.ts	0.00%	2 Missing ⚠️
src/panel/pets.ts	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #577      +/-   ##
==========================================
+ Coverage   16.58%   17.06%   +0.47%     
==========================================
  Files          23       25       +2     
  Lines        1236     1260      +24     
  Branches      167      167              
==========================================
+ Hits          205      215      +10     
- Misses       1025     1039      +14     
  Partials        6        6              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[WoofWoof0]

I had rename the gif files as requested. @tonybaloney