Description
Harbor currently requires users to manually enter their credentials when logging in via OIDC (e.g., Keycloak), even if the user is already authenticated in the browser. This differs from tools like Grafana, which support an auto_login configuration that allows users to bypass the login screen and automatically log in if a matching user session exists.

This feature request proposes adding support for an auto_login-like setting in Harbor, enabling seamless login for users who are already authenticated with the OIDC provider in their browser.

Expected Behavior
When a user visits Harbor and is already signed in to the OIDC provider (e.g., Keycloak) in the browser:
Harbor should automatically initiate the OIDC login flow.
If the user identity matches, Harbor should log the user in without prompting for credentials.
The login screen should be bypassed entirely, similar to Grafana’s auto_login = true behavior.

Benefits
Enhances user experience by removing redundant login steps.
Aligns Harbor’s behavior with other OIDC-integrated tools like Grafana.
Improves usability in enterprise environments with centralized identity and SSO.