feat: sort flights by date and add sortable date/price columns

- Change API ORDER BY from price/date to date/price (chronological default)
- Add flightSortField/flightSortDir state to ScanDetails
- Make Date and Price sub-table headers clickable with sort icons

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

flight-comparator/api_server.py

@@ -1827,7 +1827,7 @@ async def get_scan_flights(
                        departure_time, arrival_time, price, stops
                 FROM flights
                 WHERE scan_id = ? AND destination = ?
-                ORDER BY price ASC, date ASC
+                ORDER BY date ASC, price ASC
                 LIMIT ? OFFSET ?
             """, (scan_id, destination.upper(), limit, offset))
         else:
@@ -1836,7 +1836,7 @@ async def get_scan_flights(
                        departure_time, arrival_time, price, stops
                 FROM flights
                 WHERE scan_id = ?
-                ORDER BY price ASC, date ASC
+                ORDER BY date ASC, price ASC
                 LIMIT ? OFFSET ?
             """, (scan_id, limit, offset))
 

flight-comparator/frontend/src/pages/ScanDetails.tsx

@@ -54,6 +54,8 @@ export default function ScanDetails() {
   const [sortDirection, setSortDirection] = useState<'asc' | 'desc'>('asc');
   const [expandedRoute, setExpandedRoute]   = useState<string | null>(null);
   const [flightsByDest, setFlightsByDest]   = useState<Record<string, Flight[]>>({});
+  const [flightSortField, setFlightSortField] = useState<'date' | 'price'>('date');
+  const [flightSortDir, setFlightSortDir]     = useState<'asc' | 'desc'>('asc');
   const [loadingFlights, setLoadingFlights] = useState<string | null>(null);
   const [rerunning, setRerunning]           = useState(false);
   const [confirmDelete, setConfirmDelete]   = useState(false);
@@ -115,6 +117,24 @@ export default function ScanDetails() {
     }
   };
 
+  const handleFlightSort = (field: 'date' | 'price') => {
+    if (flightSortField === field) {
+      setFlightSortDir(d => d === 'asc' ? 'desc' : 'asc');
+    } else {
+      setFlightSortField(field);
+      setFlightSortDir('asc');
+    }
+  };
+
+  const sortedFlights = (flights: Flight[]) =>
+    [...flights].sort((a, b) => {
+      const aVal = flightSortField === 'date' ? a.date : (a.price ?? Infinity);
+      const bVal = flightSortField === 'date' ? b.date : (b.price ?? Infinity);
+      if (aVal < bVal) return flightSortDir === 'asc' ? -1 : 1;
+      if (aVal > bVal) return flightSortDir === 'asc' ? 1 : -1;
+      return 0;
+    });
+
   const toggleFlights = async (destination: string) => {
     if (expandedRoute === destination) { setExpandedRoute(null); return; }
     setExpandedRoute(destination);
@@ -217,6 +237,13 @@ export default function ScanDetails() {
       : <ChevronDown size={14} className="text-primary" />;
   };
 
+  const FlightSortIcon = ({ field }: { field: 'date' | 'price' }) => {
+    if (flightSortField !== field) return <ChevronUp size={12} className="opacity-30" />;
+    return flightSortDir === 'asc'
+      ? <ChevronUp size={12} className="text-secondary" />
+      : <ChevronDown size={12} className="text-secondary" />;
+  };
+
   const thCls = (field?: typeof sortField) => cn(
     'px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider select-none',
     field
@@ -670,15 +697,29 @@ export default function ScanDetails() {
                                   <table className="w-full">
                                     <thead className="bg-[#EEF7F0]">
                                       <tr>
-                                        <th className="pl-12 pr-4 py-2 text-left text-xs font-semibold uppercase tracking-wider text-on-surface-variant">Date</th>
+                                        <th
+                                          className="pl-12 pr-4 py-2 text-left text-xs font-semibold uppercase tracking-wider select-none cursor-pointer hover:bg-[#D4EDDA] transition-colors"
+                                          onClick={() => handleFlightSort('date')}
+                                        >
+                                          <span className={cn('inline-flex items-center gap-1', flightSortField === 'date' ? 'text-secondary' : 'text-on-surface-variant')}>
+                                            Date <FlightSortIcon field="date" />
+                                          </span>
+                                        </th>
                                         <th className="px-4 py-2 text-left text-xs font-semibold uppercase tracking-wider text-on-surface-variant">Airline</th>
                                         <th className="px-4 py-2 text-left text-xs font-semibold uppercase tracking-wider text-on-surface-variant">Departure</th>
                                         <th className="px-4 py-2 text-left text-xs font-semibold uppercase tracking-wider text-on-surface-variant">Arrival</th>
-                                        <th className="px-4 py-2 text-right text-xs font-semibold uppercase tracking-wider text-on-surface-variant">Price</th>
+                                        <th
+                                          className="px-4 py-2 text-right text-xs font-semibold uppercase tracking-wider select-none cursor-pointer hover:bg-[#D4EDDA] transition-colors"
+                                          onClick={() => handleFlightSort('price')}
+                                        >
+                                          <span className={cn('inline-flex items-center justify-end gap-1', flightSortField === 'price' ? 'text-secondary' : 'text-on-surface-variant')}>
+                                            Price <FlightSortIcon field="price" />
+                                          </span>
+                                        </th>
                                       </tr>
                                     </thead>
                                     <tbody className="divide-y divide-[#D4EDDA]">
-                                      {(flightsByDest[route.destination] || []).map((f) => (
+                                      {sortedFlights(flightsByDest[route.destination] || []).map((f) => (
                                         <tr key={f.id} className="hover:bg-[#EEF7F0] transition-colors">
                                           <td className="pl-12 pr-4 py-2.5 text-sm text-on-surface">
                                             <span className="font-mono text-xs font-semibold text-on-surface-variant mr-2">{weekday(f.date)}</span>