Revise README for project relocation to Codeberg

Updated README to reflect the project's move to Codeberg and included an outdated section.

Author: bitfl0wer

README.md

@@ -3,6 +3,10 @@
 >
 > We have moved to [Codeberg](https://codeberg.org/polyphony) as our primary Git Forge, and the project is *alive and well* over there! :purple_heart: The GitHub repositories will be archived and potentially deleted in the future.
 
+
+<details>
+  <summary>Old README (outdated!)</summary>
+
 <img src="https://cloud.bitfl0wer.de/apps/files_sharing/publicpreview/2qCxoXJ27yW7QNR?file=/&fileId=1143147&x=256&y=256&a=true" align="left" alt="a purple cog, split in the middle along the horizontal axis with a gap inbetween the two halves. three overlayed, offset sinus-like waves travel through that gap. each wave has a different shade of purple" width="128px" height="auto"></img>
 
 ### `typespec-openapi`
@@ -47,7 +51,7 @@ You will need the following things installed on your computer:
    the project when you save a file.
 5. The compiled OpenAPI3 schema will be in the `$PROJECT/tsp-output/@typespec/openapi3` directory.
 
-[Discord]: https://dcbadge.vercel.app/api/server/m3FpcapGDD?style=flat
-[Discord-invite]: https://discord.com/invite/m3FpcapGDD
 [Code-of-conduct-shield]: https://img.shields.io/badge/Code_of_Conduct-eb00ff
-[Code-of-conduct]: https://github.com/polyphony-chat/.github/blob/main/CODE_OF_CONDUCT.md
+[Code-of-conduct]: https://github.com/polyphony-chat/.github/blob/main/CODE_OF_CONDUCT.md
+
+</details>