Improve shortcuts in video player in web client

[user7]

The current video player lacks proper hotkey functionality. Instead, users must navigate through the UI using the TAB key and interact with specific elements to control playback. Consider the sequence of actions:

1. Video Starts: No shortcuts work initially. Space doesn’t pause, arrow keys do nothing.
2. To Pause: Press TAB TAB SPACE (focus on the "Play/Pause" button and press it)
3. To Rewind: Now SPACE works to pause/resume, but you can't skip back/forward. To rewind press TAB TAB TAB LEFT. This is to focus on the "Video Progress" element. This element supports LEFT/RIGHT to skip back/forward and SPACE to pause/resume, but doesn't support adjusting volume or muting.
4. To Mute: Press SHIFT-TAB SHIFT-TAB SPACE. For the mute button SPACE works to mute/unmute, no longer pausing/resuming the video.
5. To Increase Volume: Press TAB UP. For the volume control SPACE does nothing.

This constant tabbing between elements makes keyboard control cumbersome. To improve usability, implement universal hotkeys that work regardless of UI focus, e.g.:

SPACE: Always pause/resume.
LEFT/RIGHT: Always skip back/forward.
UP/DOWN: Always adjust volume up/down.
0...9: Jump to 0%...90% of the video.
M: Toggle mute.
F: Toggle full screen.