Add the ability to take snapshots when viewing history of cameras

[nrlcode]

Describe what you are trying to accomplish and why in non technical terms
When reviewing footage in the History / Recording viewer, there is no direct way to save the current playback frame as a snapshot.

Right now, users can take snapshots from live view, but that does not help when they are reviewing a past moment in History and want to export the exact frame they are currently paused on or scrubbing through.

This is especially useful when:

• reviewing an event after it happened
• exporting a frame for documentation or sharing
• capturing a specific moment from recorded footage rather than the current live feed

Describe the solution you'd like
Add a snapshot action to the History / Recording player controls.

Expected behavior:

• Capture the currently displayed playback frame from the recorded video being viewed
• Download it as an image
• Name the file using the playback/timeline timestamp rather than the current wall-clock time
• Use the same timezone context shown in the Frigate UI/timeline so the downloaded filename matches what the user sees in History

Describe alternatives you've considered
Current alternatives are not ideal:

• Taking a live snapshot does not capture the recorded moment being reviewed
• Manual screenshots are lower quality and less convenient
• Exporting video clips is heavier than needed when only a single frame is desired

Additional context
This would make History review workflows more complete and bring useful parity with live-view capture behavior while staying focused on recorded playback.

[nrlcode]

@hawkeye217 any reason you're not necessarily onboard with the history snapshot functionality? Is it the way it is implemented, or just the feature itself?

[NickM-27]

It's currently possible to do this in most browsers via right click, but this does align with a similar feature on the live view

[hawkeye217]

@hawkeye217 any reason you're not necessarily onboard with the history snapshot functionality? Is it the way it is implemented, or just the feature itself?

I am slightly hesitant for the feature itself as right clicking is the usual browser-supported way to do this. But as @NickM-27 mentioned, I think it's fine to implement here too, it shouldn't add any support burden.

[nrlcode]

Ah, I didn't realize that. Looks like it does work on desktop! On mobile however the functionality is hit or miss depending on the browser, it doesn't work on Safari or Brave on iOS. So there is some utility there for allowing it to work on Mobile.