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/templates/apps/dashboard/_partials/_applet-my-sky.html

@@ -85,9 +85,17 @@
 
   {% if request.user.sky_chart_data %}
 
-  // Sky already saved — draw the stored wheel immediately.
-  const data = JSON.parse(document.getElementById('id_my_sky_data').textContent);
-  NatusWheel.preload().then(function () { NatusWheel.draw(svgEl, data); });
+  // Sky already saved — fetch fresh enriched data from server then draw.
+  fetch('{% url "sky_natus_data" %}')
+    .then(function (r) { return r.ok ? r.json() : Promise.reject(r.status); })
+    .then(function (data) {
+      NatusWheel.preload().then(function () { NatusWheel.draw(svgEl, data); });
+    })
+    .catch(function () {
+      // Fallback: draw from inline stale data if endpoint fails.
+      var stale = JSON.parse(document.getElementById('id_my_sky_data').textContent);
+      NatusWheel.preload().then(function () { NatusWheel.draw(svgEl, stale); });
+    });
 
   {% else %}