natus tooltip: fix portal placement + viewport clamping + SVG sign icon

- Move #id_natus_tooltip out of #id_applets_container (container-type:
  inline-size breaks position:fixed) → add to home.html alongside
  #id_tooltip_portal
- Move #id_natus_tooltip out of .natus-modal-wrap (transform breaks
  position:fixed) → place as sibling of .natus-overlay in room.html
- Add _positionTooltip() helper in natus-wheel.js: flips tooltip to
  left of cursor when it would overflow right edge; clamps both axes
- Replace hardcoded 280px in dashboard.js palette tooltip with measured
  offsetWidth; add left-edge floor (Math.max margin)
- Planet tooltip format: @14.0° Capricorn (<svg-icon>) using preloaded
  _signPaths; falls back to unicode symbol if not yet loaded
- Add .tt-sign-icon SCSS: fill:currentColor, vertical-align:middle

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

src/templates/apps/gameboard/room.html

@@ -71,6 +71,10 @@
         {% if room.table_status == "SKY_SELECT" %}
             {% include "apps/gameboard/_partials/_natus_overlay.html" %}
         {% endif %}
+        {# Natus tooltip: sibling of .natus-overlay, not inside .natus-modal-wrap (which has transform) #}
+        {% if room.table_status == "SKY_SELECT" %}
+            <div id="id_natus_tooltip" class="tt" style="display:none;"></div>
+        {% endif %}
 
         {% if room.gate_status != "RENEWAL_DUE" and room.table_status != "SIG_SELECT" %}
             {% include "apps/gameboard/_partials/_table_positions.html" %}