Reduce fonts files size

[meduzen]

Follow-up of #129:

• replace Oxygen bold v13 by a subset of v15
• update Oxygen regular to v15, which is half the size 🥳

[what-the-diff]

PR Summary

• Optimization of Font Files
  The changes focus on including only *.woff2 font files in the project to improve load performance.

• Version and File Path Updates
  The versions of oxygen-mono.css and oxygen.css files have been updated along with modification in file paths for certain fonts, ensuring we are using the latest versions and correct file locations.

• Service Worker Updates
  The service worker, which helps with offline capabilities, is updated to use newly defined subset versions of oxygen-bold and oxygen-mono fonts.

• Added New Font files
  New subset font files like oxygen-bold-subset-auto.woff2 and others have been added aimed at improving web performance.

• File Renaming and Moving
  Various font files like oxygen-bold.woff2 and oxygen-light.woff2 have been renamed and moved to an "unused" folder, likely reflecting changes in the site's typography or optimizing the project structure.

• Adjusting File Permissions
  The permissions of oxygen-regular.woff2 have been adjusted for potential security improvements.

• Documentation Addition
  A new README.md file has been added to the unused fonts folder, possibly for better file and project management.

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
Everything	281.9 KB (-0.91% 🔽)	5.7 s (-0.91% 🔽)	5.9 s (-14.09% 🔽)	11.6 s
HTML	4.4 KB (0%)	88 ms (0%)	0 ms (+100% 🔺)	88 ms
CSS	3.64 KB (+0.22% 🔺)	73 ms (+0.22% 🔺)	0 ms (+100% 🔺)	73 ms
JS	6.76 KB (+0.16% 🔺)	136 ms (+0.16% 🔺)	6.7 s (+0.4% 🔺)	6.9 s
Fonts	12.47 KB (-78.54% 🔽)	250 ms (-78.54% 🔽)	0 ms (+100% 🔺)	250 ms
Sounds (FLAC)	125.78 KB (0%)	2.6 s (0%)	0 ms (+100% 🔺)	2.6 s
Sounds (WAV)	168.79 KB (0%)	3.4 s (0%)	0 ms (+100% 🔺)	3.4 s

[meduzen]

App fonts weight down from 41 KB to 13 KB.