Fix stale README module names

[AlexanderTrysMine]

Summary

• fix the WorldGuard amd WorldEdit typo in the requirements list
• update the module table to match the current Gradle module layout after the backend/API split
• add the missing
  ealty-paper-api entry to the README

Testing

• not run locally: the repo requires a Java 21 toolchain, but this machine only exposed Java 25 plus a Java 21 JRE, so Gradle could not compile the project