Dashboard URLs return 404 errors after RHOAI upgrade from 2.x to 3.x

Issue

After upgrading Red Hat OpenShift AI from version 2.x to 3.x, the dashboard is no longer accessible through previously bookmarked URLs. You might observe the following symptoms:

• Accessing saved dashboard URLs returns HTTP 404 Not Found error or "Application is not available" messages.
• The rhods-dashboard route no longer exists.
• Documentation and training materials with previously distributed dashboard links no longer function.
• Users cannot access the dashboard using previously bookmarked links.