Unified camera panel (no-reparent) — prototype

[danielchalmers]

Prototype for evaluation (not ready to merge)

Reworks the video area into a single CameraLayoutPanel holding all four players, so they're never reparented — switching views just re-arranges/resizes them in place, which eliminates the camera-switch flash.

• Grid view: 2x2.
• Single view: selected camera fills the top; the other three as a strip of tiles along the bottom of the video area.
• The bottom dashcam bar is now static switch buttons (single-screen icon + label) since the live previews moved into the panel.
• Removed all the reparenting code-behind (UpdateCameraHostLayout/MoveHostToSlot/etc.).

Known gaps in this prototype

• Click-to-switch on the in-video minis isn't wired — the transparent overlay-inside-host click didn't actually fire (Flyleaf surface input is trickier than the docs implied). Switching is via the bottom buttons for now; I'll solve in-video clicks properly if you like this layout.
• Camera labels over the video aren't added yet.

Verification

Build clean, 93 tests pass, smoke-launch clean. The layout itself needs your eyes.

[danielchalmers]

Closing — the unified-panel layout isn't the direction; keeping the dedicated bottom bar. Pursuing WPF-composited (D3DImage) video rendering instead to fix the underlying airspace issues.