feat: add smart flight tracking with AviationStack API + visual progress

- Add 20+ flight fields (terminal, gate, delays, estimated times, etc.)
- Smart polling cron with budget-aware priority queue (100 req/month)
- Tracking phases: FAR_OUT → PRE_DEPARTURE → ACTIVE → LANDED
- Visual FlightProgressBar with animated airplane between airports
- FlightCard with status dots, delay badges, expandable details
- FlightList rewrite: card-based, grouped by status, search/filter
- Dashboard: enriched flight status widget with compact progress bars
- CommandCenter: flight alerts + enriched arrivals with gate/terminal

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

frontend/src/hooks/useFlights.ts

@@ -0,0 +1,65 @@
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { api } from '@/lib/api';
+import { Flight, FlightBudget } from '@/types';
+import toast from 'react-hot-toast';
+
+export function useFlights() {
+  return useQuery<Flight[]>({
+    queryKey: ['flights'],
+    queryFn: async () => {
+      const { data } = await api.get('/flights');
+      return data;
+    },
+    refetchInterval: 60000, // Refresh from DB every 60s (free, no API cost)
+  });
+}
+
+export function useFlightBudget() {
+  return useQuery<FlightBudget>({
+    queryKey: ['flights', 'budget'],
+    queryFn: async () => {
+      const { data } = await api.get('/flights/tracking/budget');
+      return data;
+    },
+    refetchInterval: 300000, // Every 5 min
+  });
+}
+
+export function useRefreshFlight() {
+  const queryClient = useQueryClient();
+
+  return useMutation({
+    mutationFn: async (flightId: string) => {
+      const { data } = await api.post(`/flights/${flightId}/refresh`);
+      return data;
+    },
+    onSuccess: (data) => {
+      queryClient.invalidateQueries({ queryKey: ['flights'] });
+      queryClient.invalidateQueries({ queryKey: ['flights', 'budget'] });
+      const status = data.status || 'unknown';
+      toast.success(`Flight updated: ${data.flightNumber} (${status})`);
+    },
+    onError: (error: any) => {
+      toast.error(error.response?.data?.message || 'Failed to refresh flight');
+    },
+  });
+}
+
+export function useRefreshActiveFlights() {
+  const queryClient = useQueryClient();
+
+  return useMutation({
+    mutationFn: async () => {
+      const { data } = await api.post('/flights/refresh-active');
+      return data;
+    },
+    onSuccess: (data) => {
+      queryClient.invalidateQueries({ queryKey: ['flights'] });
+      queryClient.invalidateQueries({ queryKey: ['flights', 'budget'] });
+      toast.success(`Refreshed ${data.refreshed} flights (${data.budgetRemaining} API calls remaining)`);
+    },
+    onError: (error: any) => {
+      toast.error(error.response?.data?.message || 'Failed to refresh flights');
+    },
+  });
+}