Phase 2c: eclipse/overpass calculators + live-map camera polish

Calculators (apps/live-map/src/calculators/):
- eclipse.ts: findEclipseWindows(bodies, opts) — coarse scan with
  threshold-crossing detection, bisection to refine start/end,
  ternary search to find peak. Handles eclipse already in progress
  at scan-start. Uses sun = parentId===null body.
- overpass.ts: findOverpasses(opts) — coarse scan for local distance
  minima, ternary refinement. Targets: vessel, body, ground station
  (lat/lon/alt → heliocentric).

UI:
- panels/CalculatorsPanel.tsx: collapsible bottom-center panel with
  two tabs. Eclipse form: observer, eclipser, from UT → 3 windows.
  Overpass form: observer vessel, target kind+id, max dist → 5 passes.
- timeFormat.ts: shared KSP-time formatters.

Live-map camera polish (apps/live-map/src/scene/):
- camera.ts: CameraController — log-scale distance (z→exp(z)*1e8 m,
  range -3..12), spherical orbit around target, smooth lerp to
  selected body/vessel. Mouse wheel zooms, drag rotates, click
  raycasts for track toggle. Pointer-move-distance gate to
  distinguish click from drag.
- glow.ts: additive shader-based atmospheric halo (rim-falloff
  fragment shader, BackSide) attached as child of body mesh.
- layout.ts: bodyPositionAt now returns true heliocentric (walks
  parent chain); previous version returned parent-relative for
  non-root children which broke the eclipse calculator.

Bug fix:
- packages/orbital-math/src/occultation.ts: sign of projection check
  was inverted. `proj <= 0` correctly returns 0 (occluder behind
  observer), `proj > 0` triggers eclipse computation.

Tests: 28 live-map tests (10 scene + 12 calculator + 6 camera),
45 total across the workspace, all passing.

packages/orbital-math/src/occultation.ts

@@ -28,10 +28,14 @@ export function shadowFraction(
   const sy = observerToSun.y / sunDist;
   const sz = observerToSun.z / sunDist;
 
-  // Project occluder center onto the sun-direction line
+  // Project occluder center onto the sun-direction line.
+  // Both `observerToSun` and `occluderToObserver` point AWAY from
+  // the observer (toward the sun / toward the occluder). When the
+  // occluder sits between observer and sun, both vectors point in
+  // roughly the same direction and `proj` is positive.
   const proj = occluderToObserver.x * sx + occluderToObserver.y * sy + occluderToObserver.z * sz;
-  if (proj >= 0) {
-    // Occluder is behind the observer relative to the sun → no eclipse
+  if (proj <= 0) {
+    // Occluder is behind the observer (opposite direction from sun) → no eclipse
     return 0;
   }
   // Perpendicular distance from occluder center to sun ray