How do I read the current stage of SST in a Function (AWS Lambda)

I have an SST project, and I would like to read the current stage in order to determine if the function is running in dev mode/testing mode or production in order to switch some behaviour. My root sst.env.config looks something like this:

export default $config({
  app(input) {
    return {
      name: "my-project",
      removal: input?.stage === "production" ? "retain" : "remove",
      home: "aws",
    };
  },
  async run() {
    // some imports here
    return {
      // some exports here
      Region: aws.getRegionOutput().name,
    };
  },
});

I see in there that I can read the current stage in the "input" parameter of the app function, but I have no idea how I get it out of the SST context into the Lambda context. There is some documentation from SST 2.x that shows you can do it like this:

import { Config } from "sst/node/config";

Config.APP;
Config.STAGE;

But that import no longer works in 3.x, since you are now expected to import your local sst.env.d.ts file, not a dependency. I have also tried to get the stage via the Resource class, but no dice.

Does anyone have an idea on how to do this in SST 3.x?

In your lambda function you can now import Resource from "sst":

import { Resource } from "sst"

console.log(Resource.App.stage)