Add activity detail screenshot

README.md

@@ -7,7 +7,8 @@ The project is built for people who want the feel of a polished health app witho
 ## Screenshots
 
 <p align="center">
-  <img src="docs/screenshots/overview.png" alt="VYTA overview dashboard" width="360" />
+  <img src="docs/screenshots/overview.png" alt="VYTA overview dashboard" width="320" />
+  <img src="docs/screenshots/activity-detail.png" alt="VYTA Garmin activity detail" width="320" />
 </p>
 
 ## What It Does
@@ -189,3 +190,4 @@ python sync.py
 VYTA is a personal, self-hosted health app. It is not a medical device and does not provide clinical advice.
 
 
+