[beetlebugorg]

What changes

The build writes build/lambda-linux-<arch>.zip. Terraform read ../build/lambda-<arch>.zip, so filebase64sha256 failed and make deploy-lambda-arm64 could not apply.

• Read ../build/lambda-linux-${var.platform}.zip in the Lambda module.
• Add a platform variable to the root module and pass it to the child. An amd64 deploy no longer needs an edit to the child default. The variable accepts arm64 and amd64.
• Map the platform to the AWS architecture name. The build names its artifact with the Go architecture, amd64, while aws_lambda_function.architectures takes x86_64. Passing amd64 straight through would have been rejected by AWS, so the pass-through alone would not have made an amd64 deploy work.

Verify

terraform validate and terraform fmt -check -recursive pass.

terraform console in the Lambda module resolves both platforms:

platform=arm64  ->  ["../build/lambda-linux-arm64.zip", "arm64"]
platform=amd64  ->  ["../build/lambda-linux-amd64.zip", "x86_64"]

Dockerfile.lambda line 27 writes lambda-linux-${TARGETARCH}.zip, and a make lambda-amd64 run exports lambda-linux-amd64.zip. The names match.