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/static_src/scss/_natus.scss

@@ -449,7 +449,9 @@ html.natus-open .natus-modal-wrap {
 .nw-element--air   { fill: rgba(var(--priCy,  64, 144, 176), 0.92); stroke: rgba(var(--quaUser), 1); stroke-width: 0.5px; }
 .nw-element--water { fill: rgba(var(--priId,  80,  80, 160), 0.92); stroke: rgba(var(--quaUser), 1); stroke-width: 0.5px; }
 
-// ── Planet hover tooltip — uses .tt base styles; overrides position + z ───────
+// ── Planet hover tooltip — must live outside any ancestor with transform or
+//    container-type (both break position:fixed). Placed as a direct sibling of
+//    .natus-overlay in room.html; alongside #id_tooltip_portal in home.html. ──
 
 #id_natus_tooltip {
     position: fixed;
@@ -459,6 +461,7 @@ html.natus-open .natus-modal-wrap {
 
     .tt-title       { font-size: 1rem; font-weight: 700; }
     .tt-description { font-size: 0.75rem; }
+    .tt-sign-icon   { fill: currentColor; vertical-align: middle; margin-bottom: 0.1em; }
 
     // Planet title colors — senary (brightest) tier on dark palettes
     .tt-title--au { color: rgba(var(--sixAu), 1); }  // Sun