Add video playback progress overlay

[kanihal]

Summary

• Add a bottom overlay progress bar for zoomed videos
• Show elapsed and total playback time when media duration is available
• Hide the progress overlay for streams/media without a finite duration

Validation

• node --check js/hoverzoom.js
• git diff --check -- js/hoverzoom.js

[gemini-code-assist]

Code Review

This pull request introduces a playback progress bar overlay for video elements in HoverZoom, including custom CSS styling, a time formatting helper, and event-driven updates. The review feedback highlights a potential memory leak and redundant execution issue caused by registering duplicate event listeners on the same video element when addPlaybackProgress is called multiple times. A fix is suggested to clean up previously registered listeners before adding new ones.

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