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>

CLAUDE.md

@@ -110,7 +110,7 @@ Drop → RESERVED → confirm/reject. `_gate_context()` builds slot state; `_exp
 `epic:room` view at `/gameboard/room/<uuid>/`. `gatekeeper` redirects there when `table_status` is set. Error redirects in `select_role`/`select_sig` use `epic:room` if `table_status` is set, else `epic:gatekeeper`.
 
 ## SCSS Import Order
-`core.scss`: `rootvars → applets → base → button-pad → dashboard → gameboard → palette-picker → room → card-deck → natus → tray → billboard → tooltips → game-kit → wallet-tokens`
+`core.scss`: `rootvars → applets → base → button-pad → dashboard → gameboard → palette-picker → room → card-deck → sky → tray → billboard → tooltips → game-kit → wallet-tokens`
 
 ## Critical Gotchas