rename natus → sky across the codebase — natal chart abstraction is now sky throughout, since chart inputs aren't birthday-gated

Mechanical rename: 5 files (sky-wheel.js, _sky.scss, _sky_overlay.html, SkyWheelSpec.js x2), 24 in-place edits across templates/views/urls/SCSS/JS/tests/CLAUDE.md. URL names epic:natus_save → epic:sky_save (epic namespaced, no clash w. dashboard:sky_save), JS module NatusWheel → SkyWheel, DOM ids id_natus_* → id_sky_*, BEM classes natus-* → sky-*, dashboard sky_natus_data/sky_natus_preview collapsed to sky_data/sky_preview_data. No DB migration needed (User.sky_chart_data + GameEvent.SKY_SAVED already used sky-prefix). 778 ITs + Jasmine green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/apps/dashboard/urls.py

@@ -17,6 +17,6 @@ urlpatterns = [
     path('sky/', views.sky_view, name='sky'),
     path('sky/preview', views.sky_preview, name='sky_preview'),
     path('sky/save', views.sky_save, name='sky_save'),
-    path('sky/data', views.sky_natus_data, name='sky_natus_data'),
+    path('sky/data', views.sky_data, name='sky_data'),
     path('set-pronouns', views.set_pronouns, name='set_pronouns'),
 ]