Add Trickplay support like in the official client

[mrfoggg]

Is your feature request related to a problem?
Currently, tsukimi does not support Trickplay (fast forward, rewind, or frame-accurate scrubbing) similar to the official client. This limits usability when browsing long videos or skipping to specific scenes.

Describe the solution you'd like
It would be great to have Trickplay support implemented, ideally using the same backend approach as the official client (mpv or GStreamer), allowing smooth fast-forward and rewind with visible frame previews if possible.

Describe alternatives you've considered
Currently, only basic seeking is available, which is not frame-accurate and can be slow for long videos.