Video Widget Features

Cockpit should have a core widget for displaying a video stream.

- [x] must allow specifying the stream source (most likely using WebRTC)
- [x] must support being resized
- [x] should maintain aspect ratio by default
- [x] should allow cropping when not maintaining aspect ratio
- [x] could allow stretching (i.e. to maximise viewing amount in a given area)
- [ ] could indicate the displayed resolution vs the stream resolution
- [ ] may allow automatically reducing the resolution of any stream that's being displayed at a resolution below the next available step down (or some small amount larger than it)
- [x] should support recording of incoming video
- [ ] should support image capture of currently displayed frame
- [ ] should support rotations (see #20)
- [ ] should support changing camera/stream parameters where possible
- [ ] may support simple video processing (e.g. visibility enhancement)
- [ ] may support recording and/or capture of processed display output

No files, tests, or entry points are identified. Start by locating the existing widget and video-stream architecture, then clarify which unchecked capabilities are in scope; done should be defined by tests or acceptance criteria for the selected features.

Written by the indexing model from the issue text.