Align atik.Camera interface with stx.Camera

Add all missing methods and properties so both drivers are
interchangeable in the sequencer templates:
- set_window(start_x, start_y, width, height)
- ready, setpoint, fan, ambient, center, xrange, yrange, is_moving

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>