fix: evaluated field on event list + abort race condition

- Backend: add evaluated subquery column to list SELECT so each event
  returns evaluated=1/0 (was missing, causing all events to appear
  as unevaluated regardless of filter)
- Frontend: AbortController cancels the previous in-flight fetch when
  a new load fires, preventing stale results from overwriting current
  filter state

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

backend/routers/market_events.py

@@ -171,7 +171,13 @@ def list_events(
     # When joining with instrument_impacts an event can appear multiple times — use GROUP BY
     group_sql = "GROUP BY me.id" if instrument else ""
 
-    # Extra column: best instrument score for display
+    # Extra columns: evaluated flag + optional instrument score
+    evaluated_col = (
+        ", (CASE WHEN EXISTS ("
+        "SELECT 1 FROM instrument_impacts _ei "
+        "WHERE _ei.source_type='event' AND _ei.source_id=me.id"
+        ") THEN 1 ELSE 0 END) as evaluated"
+    )
     inst_col = (
         ", MAX(COALESCE(ii.adjusted_score, ii.impact_score)) as inst_score"
         ", ii.direction as inst_direction"
@@ -181,7 +187,7 @@ def list_events(
         SELECT COUNT(DISTINCT me.id) FROM market_events me {join_clause} {where_sql}
     """
     data_sql = f"""
-        SELECT me.* {inst_col}
+        SELECT me.* {evaluated_col} {inst_col}
         FROM market_events me {join_clause}
         {where_sql} {group_sql} {order_sql}
         LIMIT ? OFFSET ?

frontend/src/pages/MarketEvents.tsx

@@ -1173,9 +1173,15 @@ export default function MarketEvents() {
     setDateTo(to)
   }, [])
 
-  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const debounceRef  = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const abortRef     = useRef<AbortController | null>(null)
 
   const load = useCallback(async () => {
+    // Cancel any in-flight fetch
+    abortRef.current?.abort()
+    abortRef.current = new AbortController()
+    const signal = abortRef.current.signal
+
     setLoading(true)
     const params = new URLSearchParams()
     if (search)    params.set('search', search)
@@ -1193,11 +1199,15 @@ export default function MarketEvents() {
     params.set('sort_by',  instTicker ? 'instrument_score' : sortBy)
     params.set('sort_dir', sortDir)
     params.set('limit', '500')
-    const r = await fetch(`/api/market-events?${params}`)
-    if (r.ok) {
-      const d = await r.json()
-      setEvents(d.events)
-      setTotal(d.total)
+    try {
+      const r = await fetch(`/api/market-events?${params}`, { signal })
+      if (r.ok) {
+        const d = await r.json()
+        setEvents(d.events)
+        setTotal(d.total)
+      }
+    } catch (e: any) {
+      if (e.name === 'AbortError') return  // superseded by a newer load
     }
     setLoading(false)
   }, [search, category, level, minScore, dateFrom, dateTo, evaluated,