New pattern submission- apigw-connect-notification pattern

**### Description:**
Adds the apigw-connect-notification pattern: an API Gateway sends in-app push notifications to Amazon Connect agents and admins through a direct AWS service integration via CreateNotification API.

Level: 200

Framework: SAM

Services: API Gateway, Amazon Connect

**What is Amazon Connect Notifications?**
In-app notifications are on-screen alerts in the Amazon Connect workspace header. They're the only built-in mechanism to broadcast messages to agents/admins regardless of what page they're on. **Currently Notifications can only be sent via the API there is no console UI to compose or send them.**

**Supported use cases:**
- System notifications: availability impacts, failover events, policy changes, critical feature updates
- Custom organizational messages: training reminders, schedule adherence alerts, emergency notifications

**How it works**

- A POST /notifications REST endpoint accepts a JSON body with recipients, localized content, and optional priority/TTL.
- API Gateway transforms the request via a VTL mapping template (camelCase → PascalCase) and calls the Connect CreateNotification API directly using a PUT integration.
- An IAM role grants API Gateway the connect:CreateNotification permission. No Lambda function sits in between.
- Notifications appear in the Connect header for targeted users within seconds.

### **Resources**
- [Amazon Connect Notifications - Admin Guide](https://docs.aws.amazon.com/connect/latest/adminguide/amazon-connect-notifications.html)
- [CreateNotification API Reference](https://docs.aws.amazon.com/connect/latest/APIReference/API_CreateNotification.html)
- [API Gateway AWS Service Integration](https://docs.aws.amazon.com/apigateway/latest/developerguide/getting-started-aws-proxy.html)

### Author bio may include a LinkedIn and/or Twitter reference and a 1-sentence bio. :
"name": "Vaidehi Patel",
"bio": "Solutions Architect at Amazon Web Services",
"linkedin": "https://www.linkedin.com/in/vaidehi-patel08/"

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

## GitHub PR for template:
https://github.com/aws-samples/serverless-patterns/pull/3287

Inizia con la pull request del template collegata e il README.md del pattern. Verifica che la documentazione del pattern SAM documenti l’endpoint POST /notifications, il mapping di API Gateway, l’integrazione diretta con Amazon Connect e l’autorizzazione IAM descritta qui. Il lavoro è completato quando il pattern e tutte le sezioni richieste del README.md sono completi.

Scritto dal modello di indicizzazione a partire dal testo della issue.