extensions-app: Modernize the code
After modernizing the UI, it seems appropriate to modernize the code as well.
Namely take advantage of GTK4's list model capabilities and advanced property bindings.
Includes !3051 (merged)
After modernizing the UI, it seems appropriate to modernize the code as well.
Namely take advantage of GTK4's list model capabilities and advanced property bindings.
Includes !3051 (merged)