New pattern submission - Lambda-EndUserMessaging

[SarathKumarKS]

To submit a template to the Serverless Patterns Collection, submit an issue with the following information.

IMPORTANT
Patterns are intended to be primarily IaC-focused implementations of 2-4 AWS services, with minimum custom code. They should be commonly used combinations that help developers get started quickly. If you have a utility, demo, or application, submit these to the Serverless Repos Collection instead.

ONLY SUBMIT ONE PATTERN CHANGE PER PR. Multiple patterns or files spanning multiple pattern directories will be automatically rejected.

Patterns may take up to 4-6 weeks to review, test, and merge but there is no SLA and can take significantly longer due to other work the team has.

To learn more about submitting a pattern, read the publishing guidelines page.

1. Use the model template located at https://github.com/aws-samples/serverless-patterns/tree/main/_pattern-model to set up a README, template and any associated code.

2. THIS PROCESS HAS BEEN SIMPLIFIED. All the information below must be provided in the "example-pattern.json" file cloned from the model **

Note the following information for the model:

• Description (intro.text) should be a 300-500 word explanation of how the pattern works.

This pattern demonstrates how to send scheduled SMS messages using AWS Lambda and AWS End User Messaging with a serverless architecture. The solution uses three main components working together: EventBridge for scheduling, Lambda for processing, and End User Messaging for SMS delivery.

EventBridge uses a cron expression to trigger the Lambda function at your specified time each day. When triggered, the Lambda function retrieves phone numbers from AWS Secrets Manager, ensuring data security and compliance. The function then constructs the message and calls the End User Messaging service to send the SMS.

AWS End User Messaging SMS handles message delivery to mobile devices globally while managing carrier relationships and regulatory compliance. It supports both transactional and promotional messaging types.The solution is deployed using AWS Cloud Development Kit (CDK), making the process repeatable and version-controlled. This pattern works well for daily reminders, notifications, alerts, and scheduled communications. You can easily customize it by modifying the message content, schedule, or adding conditional logic for different scenarios.

• Resources should like to AWS documentation and AWS blogs related to the post (1-5 maximum):
  https://aws.amazon.com/pm/lambda/
  https://aws.amazon.com/end-user-messaging/

• Author bio may include a LinkedIn and/or Twitter reference and a 1-sentence bio.
  Sarath Kumar K.S is a Senior Technical Account Manager at AWS.
  "linkedin": "kssarathkumar"

You must ensure that the sections of the model README.md are completed in full.

GitHub PR for template: #2800