feat(F020): frontend infrastructure foundation

- src/lib/constants.ts: centralized route paths, labels, thresholds
- src/lib/utils.ts: formatting, color helpers, math utils
- src/hooks/: useProperties, useMatches, useFutureSignals, useNeeds
- src/components/scores/MatchScoreRing
- src/components/data-quality/DataQualityBar
- src/components/future-signals/SignalTypeBadge
- src/components/cards/SourceTypeBadge
- src/provider/AuthProvider (placeholder, swappable)
- main.tsx: AuthProvider + centralized stale time

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

src/hooks/useMatches.ts

@@ -0,0 +1,42 @@
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
+import { matchService } from '../services/matchService'
+import { STALE_MATCHES } from '../lib/constants'
+
+export function useMatches() {
+  return useQuery({
+    queryKey: ['matches'],
+    queryFn: () => matchService.getAll(),
+    staleTime: STALE_MATCHES,
+    select: (res) => res.data ?? [],
+  })
+}
+
+export function useMatchesByNeed(needId: string) {
+  return useQuery({
+    queryKey: ['matches', 'need', needId],
+    queryFn: () => matchService.getByNeed(needId),
+    staleTime: STALE_MATCHES,
+    enabled: Boolean(needId),
+    select: (res) => res.data ?? [],
+  })
+}
+
+export function useMatchesByProperty(propertyId: string) {
+  return useQuery({
+    queryKey: ['matches', 'property', propertyId],
+    queryFn: () => matchService.getByProperty(propertyId),
+    staleTime: STALE_MATCHES,
+    enabled: Boolean(propertyId),
+    select: (res) => res.data ?? [],
+  })
+}
+
+export function useApproveMatch() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (matchId: string) => matchService.approve(matchId, 'current-user'),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['matches'] })
+    },
+  })
+}