Add Kakao Big Sans to Google Fonts

[on-the-heath]

This PR adds the Kakao Big Sans font with the required metadata files.

• Family name: Kakao Big Sans
• License: Open Font License (OFL-1.1)
• Files: METADATA.pb, OFL.txt, TTF font files

[google-cla]

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[on-the-heath]

I signed it!

[chrissimpkins]

Will you please open a new project proposal issue for this family. We're excited to consider it!

[on-the-heath]

I opened a new project issue (#9024).
Please check it and let me know if any further steps are required.

[simoncozens]

Where are the font sources? It would be useful to have a source entry in the METADATA with the source repository_url and file mappings.

[on-the-heath]

Where are the font sources? It would be useful to have a source entry in the METADATA with the source repository_url and file mappings.

Thanks for your feedback.

The font was created in collaboration with type design studios under a contract.
As a result, we do not have access to the original source files (such as UFO or Glyphs files).

I understand that Google Fonts encourages open-source development and providing source files is preferred.
However, could you confirm whether the source files are mandatory for inclusion in Google Fonts?

If there are alternative ways to proceed without the source files, please let us know.
Additionally, if there are any other modifications or requirements for submission, I would appreciate your guidance.

Thank you again for your support :)