docs: add default pgAdmin login credentials to README (#66)

Author: wanyingz-dis

README.md

@@ -47,6 +47,12 @@ cp .env.example .env & make up
 
 You can login to pgAdmin at `http://localhost:8080` to see the Postgres database. The host name for registering a new server is `postgres`, and the username and password are `alphatrion` and `alphatr1on`, respectively.
 
+**Note:**  
+To log in to the pgAdmin web interface itself (before adding a server),  
+use the default credentials defined in `docker-compose.yaml`:  
+**Email:** `alphatrion@inftyai.com`  
+**Password:** `alphatr1on`
+
 ### Run a Sample Experiment
 
 Below is a simple example demonstrating how to create an experiment and log performance metrics.