Near clip plane sized to whatever's actually selected, rather than one
fixed value for every zoom level: close enough to fly right up to a tiny
true-scale body (see scale.ts's trueRadius) without the fixed default
plane (DEFAULT_NEAR_PLANE) getting there first, but never below the
float-precision floor. radius is the selected body's own true-scale
world radius, or null/0 when nothing small enough to matter is selected
(falls back to the old fixed default).
Near clip plane sized to whatever's actually selected, rather than one fixed value for every zoom level: close enough to fly right up to a tiny true-scale body (see scale.ts's trueRadius) without the fixed default plane (DEFAULT_NEAR_PLANE) getting there first, but never below the float-precision floor.
radiusis the selected body's own true-scale world radius, or null/0 when nothing small enough to matter is selected (falls back to the old fixed default).