docs(README): enhance notification streams description

- Introduce the concept of "Interests" to explain user-created content filters
- Clarify that users subscribe to notifications for specific Interests
- Improve readability and understanding of the user-crafted notification feature

Author: fulleni

README.md

@@ -76,7 +76,7 @@ The API automatically validates the structure of all incoming data, ensuring tha
 ### 📲 Dynamic & Personalized Notifications
 A complete, multi-provider notification engine that empowers you to engage users with timely, relevant, and personalized alerts.
 - **Editorial-Driven Alerts:** Any piece of content can be designated as "breaking news" from the content dashboard, triggering immediate, high-priority alerts to subscribed users.
-- **User-Crafted Notification Streams:** Users can create and save persistent notification subscriptions based on any combination of content filters (such as topics, sources, or regions), allowing them to receive alerts only for the news they care about.
+- **User-Crafted Notification Streams:** Users can create and save persistent **Interests** based on any combination of content filters (such as topics, sources, or regions). They can then subscribe to notifications for that interest, receiving alerts only for the news they care about.
 - **Flexible Delivery Mechanisms:** The system is architected to support multiple notification types for each subscription, from immediate alerts to scheduled daily or weekly digests.
 - **Provider Agnostic:** The engine is built to be provider-agnostic, with out-of-the-box support for Firebase (FCM) and OneSignal. The active provider can be switched remotely without any code changes.
 > **Your Advantage:** You get a complete, secure, and scalable notification system that enhances user engagement and can be managed entirely from the web dashboard.