Look into possibility of being able to attach bucket bar to transcript container in video player

[robertknight]

In the in-development video player app, all the annotatable content is in the transcript container. The bucket bar however is in its usual location on the right side of the screen:

I find that these buckets end up being hard to see / easy to miss as they are visually detached from the container that scrolls. A possibility that we want to explore instead is attaching the bucket bar to the transcript container. This might be connected to preventing annotation of content outside of the transcript.

• Resolve issue with merging of on-screen and off-screen buckets (Merging of buckets into top/bottom buckets happens at unexpected position #5525)
• Enable bucket bar to render into a custom container (Support rendering bucket bar inside a custom container #5524)
• Update bucket bar bucket positions if container is resized (Update bucket bar when container is resized #5550)
• Ensure top/bottom bucket scrolling works when using a custom bucket container (Support rendering bucket bar inside a custom container #5524 (comment), Make top/bottom bucket scrolling work when using a custom bucket container #5552)

[robertknight]

Some technical issues we'd need to work through:

• How does the host page specify a container to attach the bucket bar to?
• The bucket bar currently lives inside the <hypothesis-sidebar> shadow DOM, which isolates it from the page's styles. We'd probably need to extract it into its own custom element with its own shadow DOM.

[robertknight]

Work being done in this PR: #5524

[lyzadanger]

@robertknight Looks like maybe this one is good to close? Yay!

[robertknight]

Yes, this is good to close.