fix: race condition causing wrong symbol data in chart and evaluation

- Add cancelled flags to evaluation and scorecard effects so stale
  responses from a previous symbol cannot overwrite current data
- Clear evaluation and scorecard state immediately in pickSymbol so
  old data never flashes when switching symbols
- Add key={symbol} to ConfluenceChart to force clean remount on
  symbol change

app/src/components/ConfluencePanel.tsx

@@ -55,6 +55,9 @@ export function ConfluencePanel() {
     setSymbol(sym);
     setSearchQuery(sym);
     setActiveSymbol(sym);
+    // Clear stale data immediately so old symbol never flashes
+    setEvaluation(null);
+    setScorecard(null);
   }, [setActiveSymbol]);
 
   // Sync searchQuery when activeSymbol changes externally (e.g., from another panel)
@@ -62,6 +65,11 @@ export function ConfluencePanel() {
     setSearchQuery(activeSymbol);
   }, [activeSymbol]);
 
+  // Sync symbol state when activeSymbol changes externally
+  useEffect(() => {
+    setSymbol(activeSymbol);
+  }, [activeSymbol]);
+
   // Racks
   const [racks, setRacks] = useState<{ system: Array<{ id: string; name: string }>; user: Array<{ id: string; name: string }> }>({ system: [], user: [] });
   useEffect(() => {
@@ -73,18 +81,22 @@ export function ConfluencePanel() {
   const rackId = selectedRackId ?? racks.system[0]?.id ?? null;
   useEffect(() => {
     if (!symbol) return;
+    let cancelled = false;
     api.confluence.evaluation(symbol, { rackId: rackId ?? undefined, limit: 6 })
-      .then((r) => setEvaluation(r as Record<string, unknown>))
-      .catch(() => setEvaluation(null));
+      .then((r) => { if (!cancelled) setEvaluation(r as Record<string, unknown>); })
+      .catch(() => { if (!cancelled) setEvaluation(null); });
+    return () => { cancelled = true; };
   }, [symbol, rackId]);
 
   // Scorecard
   const [scorecard, setScorecard] = useState<{ slots: Array<Record<string, unknown>>; note: string } | null>(null);
   useEffect(() => {
     if (!symbol) return;
+    let cancelled = false;
     api.confluence.scorecard(symbol)
-      .then((r) => setScorecard(r as { slots: Array<Record<string, unknown>>; note: string }))
-      .catch(() => setScorecard(null));
+      .then((r) => { if (!cancelled) setScorecard(r as { slots: Array<Record<string, unknown>>; note: string }); })
+      .catch(() => { if (!cancelled) setScorecard(null); });
+    return () => { cancelled = true; };
   }, [symbol]);
 
   // Slots
@@ -194,7 +206,7 @@ export function ConfluencePanel() {
       {/* Signal Timeline chart */}
       {symbol && (
         <CollapsibleSection title="Signal Timeline" defaultOpen>
-          <ConfluenceChart symbol={symbol} />
+          <ConfluenceChart key={symbol} symbol={symbol} />
         </CollapsibleSection>
       )}