sky wheel: element contributor display; sign + house tooltips — TDD

sky_save now re-fetches from PySwiss server-side on save so stored
chart_data always carries enriched element format (contributors/stellia/
parades). New sky/data endpoint serves fresh PySwiss data to the My Sky
applet on load, replacing the stale inline json_script approach.

natus-wheel.js: sign ring slices (data-sign-name) and house ring slices
(data-house) now have click handlers with _activateSign/_activateHouse;
em-dash fallback added for classic elements with empty contributor lists.
Action URLs sky/preview, sky/save, sky/data lose trailing slashes.

Jasmine: T12 sign tooltip, T13 house tooltip, T14 enriched element
contributor display (symbols, Stellium/Parade formations, em-dash fallback).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/apps/dashboard/tests/integrated/test_sky_views.py

@@ -1,8 +1,8 @@
 """Integration tests for the My Sky dashboard views.
 
 sky_view    — GET /dashboard/sky/  → renders sky template
-sky_preview — GET /dashboard/sky/preview/  → proxies to PySwiss (no DB write)
-sky_save    — POST /dashboard/sky/save/    → saves natal data to User model
+sky_preview — GET /dashboard/sky/preview  → proxies to PySwiss (no DB write)
+sky_save    — POST /dashboard/sky/save    → saves natal data to User model
 """
 
 import json
@@ -113,14 +113,13 @@ class SkySaveTest(TestCase):
         self.assertEqual(response.status_code, 405)
 
     def test_saves_sky_fields_to_user(self):
-        chart = {"planets": {}, "houses": {}, "elements": {}}
         payload = {
             "birth_dt":    "1990-06-15T08:30:00",
             "birth_lat":   51.5074,
             "birth_lon":   -0.1278,
             "birth_place": "London, UK",
             "house_system": "O",
-            "chart_data":  chart,
+            "chart_data":  {},
         }
         response = self._post(payload)
         self.assertEqual(response.status_code, 200)
@@ -131,7 +130,6 @@ class SkySaveTest(TestCase):
         self.assertAlmostEqual(float(self.user.sky_birth_lon), -0.1278, places=3)
         self.assertEqual(self.user.sky_birth_place, "London, UK")
         self.assertEqual(self.user.sky_house_system, "O")
-        self.assertEqual(self.user.sky_chart_data, chart)
 
     def test_invalid_json_returns_400(self):
         response = self.client.post(