Add SQS trigger infrastructure for both Lambdas

[nickclyde]

Description

Both lambdas expect SQS events as input (SQSEvent typing), but there is no SQS queue, S3 event notification, or Lambda event source mapping in Terraform.

Resources Needed

TTC Lambda trigger chain:

1. SQS queue (ttc-input-queue)
2. S3 event notification on the TTC input prefix → SQS
3. Lambda event source mapping: SQS → TTC Lambda
4. Dead letter queue for failed TTC processing

Augmentation Lambda trigger chain:

1. SQS queue (augmentation-input-queue)
2. S3 event notification on the TTC output prefix → SQS
3. Lambda event source mapping: SQS → Augmentation Lambda
4. Dead letter queue for failed augmentation processing

Acceptance Criteria

• SQS queues created with appropriate visibility timeout (>= lambda timeout)
• S3 event notifications configured on our S3 bucket for relevant prefixes
• Lambda event source mappings link SQS to each Lambda
• Dead letter queues configured for both
• IAM permissions for S3 → SQS and SQS → Lambda
• Variables for queue names and DLQ retention

Depends On

• Update TTC Lambda input and output buckets #349 (prefix finalization)
• Add Terraform for Augmentation Lambda #368 (Augmentation Lambda TF)