Add AWS service account credentials for staging profiles task definition

[jrhoads]

Purpose

The purpose of this pull request is to configure AWS service account credentials for the profiles service task definition in the staging environment.

Approach

Define new Terraform variables for the AWS service account key and secret, and forward these values into the profiles_task ECS task definition template file.

Key Modifications

• stage/services/profiles/var.tf: Declared aws_service_account_key and aws_service_account_secret variables.
• stage/services/profiles/input.tf: Added aws_service_account_key and aws_service_account_secret to the data.template_file.profiles_task template variables.

Important Technical Details

• Because these variables do not have default values specified in var.tf, their values must be supplied via the environment, .tfvars, or CI/CD secrets during Terraform execution.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

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