emirkabal/better-videos-for-instagram ? reverse-engineered prompt

Build me a browser extension for Instagram that makes videos way easier to watch. I want it to let me play, pause, seek, and control the volume directly on Instagram videos, and I want the volume setting to be remembered so I do not have to keep adjusting it every time. It should also support fullscreen playback and have autoskip behavior if that is part of the experience. Please make sure it works on the common video players Instagram uses, not just one specific kind.

I need it to work in both Chrome and Firefox, and ideally be packaged so it is easy to install and run locally for testing. Keep the UI simple and clean, just enough controls to make Instagram video watching better without getting in the way. If you need to check any current browser extension docs while building it, go ahead and look them up online.