Fix what the review of this branch found, starting with the pick rule it only claimed

The off-screen rule for clicks was described in 3f0abf8 and in the pull request, but only its
comment was committed: pickAt still let the slop reach past the frame. The mutant that was said
to catch it matched nothing, and an unrelated flaky test failed instead. The frame test is now in
pickAt, before the slop, and its test fails without it (star at NDC 1.01, click at 0.995).

Venus, Uranus and Pluto turned forwards: Horizons states a retrograde spin twice, by a negative
rate and by an obliquity over 90 degrees, and both were applied. The period's sign is now used
only when no obliquity is known. Measured on the live markers, spin axis against orbit normal is
cos(obliquity) for each: Venus -0.999, Uranus -0.135, Pluto -0.494, Earth 0.917.

Moons listed as rates rather than "Synchronous" drifted about 5 degrees an orbit and Titan did not
turn: every moon is now locked at its Kepler period. Pluto's obliquity comes from IAU WGCCRE 2015,
Horizons gives none.

Also:
- the star's light is white at pi, not a warm 2.2 that left the photographs dim;
- procedural textures are 128x64, not 512x256 that froze the main thread ~60 ms a body;
- Io, Pluto, Titan and Deimos lose their "maps", which were disc photographs with black sky;
- an exoplanet with only a mass gets a radius from it (M^0.55, capped at Jupiter), not Earth's;
- the clock knows when it has left the present even once back at real time, so the date and
  "Back to now" stay up.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/app/features/hud/hud-dock.component.ts

@@ -323,7 +323,7 @@ function isWideViewport(): boolean {
                     {{ rate.label }}
                   </label>
                 }
-                @if (time.rate() !== 1) {
+                @if (!time.atNow()) {
                   <button
                     type="button"
                     (click)="time.reset()"
@@ -384,7 +384,7 @@ function isWideViewport(): boolean {
             </button>
           }
         </div>
-        <!-- Only while the clock is running faster than the world: at real time the date is
+        <!-- Only while the map is away from the present: at the present the date is
              today's, which the reader's own machine already says. -->
         @if (date()) {
           <p
@@ -418,7 +418,7 @@ export class HudDockComponent implements OnInit {
   readonly note = input('');
   /** Camera range, pre-formatted by the scene, which is the only thing that knows the units. */
   readonly range = input('');
-  /** The date the sky is drawn for; empty while the clock runs at real time. */
+  /** The date the sky is drawn for; empty while the map is drawn for the present. */
   readonly date = input('');
   /** Layer state; `null` means the surface has no layers to toggle and no Display tab. */
   readonly display = input<HudDisplay | null>(null);