fix(sat): saving the settings refreshes the Satellites tab

The tab read the followed list, the horizon and the locator once, when it
was mounted. It is normally open BEHIND the settings window while those
are edited, so un-following QO-100 left it in the pass table and in the
dropdown until the tab was reopened — indistinguishable, from the
outside, from a setting that had not saved at all.

SaveSatSettings now emits sat:settings, and the panel reloads the birds
and the passes on it, the same way it already does on sat:tle. One event
for every key: they all change what the tab should be showing. The
selection needs nothing new — a satellite that has stopped being
followed drops out of the dropdown, and the effect that keeps the
selection inside that list moves to the first one remaining.

frontend/src/components/SatellitePanel.tsx

@@ -306,6 +306,12 @@ export function SatellitePanel({ myGrid }: { myGrid: string }) {
 
   useEffect(() => { loadBirds(); loadTle(); loadPasses(); }, [loadBirds, loadTle, loadPasses]);
   useEffect(() => EventsOn('sat:tle', () => { loadTle(); loadBirds(); loadPasses(); }), [loadTle, loadBirds, loadPasses]);
+  // Saving the satellite settings. The followed list, the lowest pass and the
+  // locator all change what belongs here, and this tab is normally open behind
+  // the settings window while they are edited. The selection repairs itself:
+  // a satellite that is no longer followed drops out of the dropdown, and the
+  // effect below moves to the first one that is.
+  useEffect(() => EventsOn('sat:settings', () => { loadBirds(); loadPasses(); }), [loadBirds, loadPasses]);
   useEffect(() => { if (sel) localStorage.setItem('opslog.satSelected', sel); }, [sel]);
   useEffect(() => { setTpIdx(0); }, [sel]);