Fix satellite ground track to show full orbit

- Fix property name mismatch: backend returns 'track' but index.html
  expected 'orbitTrack'
- Start position updates when a pass is selected (was never called)
- Fetch position immediately on pass selection for instant orbit display
- Dashboard: always show full orbit track, not just when no pass selected

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/satellite_dashboard.html

@@ -1385,9 +1385,8 @@
                         satMarker = L.marker([pos.lat, pos.lon], { icon: satIcon }).addTo(groundMap);
                     }
 
-                    // Only update orbit track if no pass is selected
-                    // When a pass is selected, keep showing that pass's ground track
-                    if (selectedPass === null && pos.track && groundMap) {
+                    // Always show full orbit track from position data
+                    if (pos.track && groundMap) {
                         if (orbitTrack) groundMap.removeLayer(orbitTrack);
                         if (trackLine) groundMap.removeLayer(trackLine);
                         trackLine = null;