Add EC2 API retry config to handle RequestLimitExceeded throttling

Configure botocore with 15 total retry attempts using standard mode
to handle EC2 RunInstances API throttling when multiple VPUs launch
simultaneously.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: harshavemula-ua

infra/aws/terraform/modules/orchestration/lambdas/start_ami/lambda_function.py

@@ -1,9 +1,19 @@
 import boto3
 import botocore
+from botocore.config import Config
 import time, os, json
 
+# Configure retry for EC2 API throttling (RequestLimitExceeded)
+# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/retries.html
+retry_config = Config(
+    retries={
+        'total_max_attempts': 15,
+        'mode': 'standard'
+    }
+)
+
 global client_ec2
-client_ec2 = boto3.client('ec2',region_name=os.environ['AWS_REGION'])
+client_ec2 = boto3.client('ec2', region_name=os.environ['AWS_REGION'], config=retry_config)
 
 REGION_NAME_MAP = {
     "us-east-1": "US East (N. Virginia)",