Add info about App.js 2025 conference (#7154)

* App.js 2025

* reorder

Author: piaskowyk

src/content/community/conferences.md

@@ -15,6 +15,11 @@ December 13 & 16, 2024. In-person in Berlin, Germany + remote (hybrid event)
 
 [Website](https://reactday.berlin/) - [Twitter](https://x.com/reactdayberlin)
 
+### App.js Conf 2025 {/*appjs-conf-2025*/}
+May 28 - 30, 2025. In-person in Kraków, Poland + remote
+
+[Website](https://appjs.co) - [Twitter](https://twitter.com/appjsconf)
+
 ### React Summit 2025 {/*react-summit-2025*/}
 June 13 - 17, 2025. In-person in Amsterdam, Netherlands + remote (hybrid event)