- Add `flight` blocks to Fighter, Bomber, and Hover Constructor in rules JSON
defining height, takeoff time, and landing time
- Implement purely cosmetic altitude system: units ease upward when given
orders and settle back down when idle, using smoothstep easing
- Shadow stays pinned to ground position, fades in and shrinks as altitude
increases — the gap between body and shadow sells the height
- Health/build bars move with the lifted body; selection ring stays on ground
- Add production dials (progress pies) on the player's own factories:
top-left shows whole queue progress, top-right shows unit on the bench
- Pass real delta time to render() for framerate-independent takeoff animation
- Update sprites.md with flight system docs and art implications
- Add stub scene support and comprehensive verification tests