core rules

Whenever a new protocol message is added to the protocol/ directory, check the following:

• It's type is defined correctly
• If it is a message from webview to core or vice versa:
  • It has been added to core/protocol/passThrough.ts
  • It has been added to extensions/intellij/src/main/kotlin/com/github/continuedev/continueintellijextension/constants/MessageTypes.kt
• It is implemented in either core/core.ts (for messages to the core), in a useWebviewListener (for messages to the gui), or in VsCodeMessenger.ts for VS Code or IdeProtocolClient.kt for JetBriains (for messages to the IDE).
• It does not duplicate functionality from another message type that already exists.