Lower the star halo floor so the inner orbits stay legible

The floor that stopped the Sun disappearing reached past Venus and up to
Earth, covering the two orbits it most needed to leave alone.

Halved, from 3.5% of the framed radius to 2%. The halo's visual radius is
half its extent, so that puts its edge at 1% of the framed radius, and the
orbits it has to clear sit at their own fraction of the same radius: in
the solar system, framed to hold Pluto, Venus is at 1.3% and Earth at
1.8%. Both are now outside it, and the star still reads at about nine
pixels across on a typical window.

Mercury, at 0.7%, is still inside — and would be at any halo large enough
to see, since its orbit is only three pixels wide at that range. That is
now a pinned test rather than an oversight.

The floor was only ever the lower bound; the tests now state the upper one
too, in the terms the trade is actually made in — pixels on screen for
visibility, AU against real orbits for clearance.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WaySiNst4HhDXBHnMy8p5G

src/app/features/galaxy-system/system-framing.ts

@@ -41,9 +41,16 @@ const STAR_RADIUS_TO_INNERMOST_ORBIT = 0.45;
  * The halo resolves it, because light is not a surface: a glow that reaches past the innermost
  * orbit does not claim the star is that large, it claims the star is bright. So the disc stays
  * honest to the orbits and the halo is floored against the frame.
+ *
+ * The floor is set by what it must not cover. Its visual radius is half the extent, so a floor
+ * of `f` puts the halo's edge at `f / 2` of the frame radius — and the orbits it has to leave
+ * legible sit at their own fraction of that same radius. In the solar system, framed to hold
+ * Pluto, Venus's orbit is at 1.3% of the frame radius and Earth's at 1.8%, so a floor of 2%
+ * leaves both of them outside the halo. Mercury's, at 0.7%, is inside it — and would be at any
+ * halo large enough to see, since the orbit itself is only a few pixels wide there.
  */
 const STAR_GLOW_TO_MARKER = 3.2;
-const MIN_STAR_GLOW_TO_FRAME = 0.035;
+const MIN_STAR_GLOW_TO_FRAME = 0.02;
 
 /**
  * Clear space left around the framed radius, as a fraction of it. The camera backs off this