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/components/scores/MatchScoreRing.tsx

@@ -0,0 +1,57 @@
+import { Box, Typography } from '@mui/material'
+import { matchScoreColor } from '../../lib/utils'
+import type { MatchStrength } from '../../domain/enums'
+import { MATCH_STRENGTH_LABELS } from '../../lib/constants'
+
+interface MatchScoreRingProps {
+  score: number
+  strength: MatchStrength
+  size?: 'sm' | 'md' | 'lg'
+  showLabel?: boolean
+}
+
+const SIZE_MAP = {
+  sm: { ring: 48, font: '0.875rem', label: '0.625rem' },
+  md: { ring: 64, font: '1.125rem', label: '0.75rem' },
+  lg: { ring: 80, font: '1.5rem', label: '0.8125rem' },
+}
+
+const COLOR_MAP = {
+  success: '#1a7a4a',
+  warning: '#d97706',
+  error: '#c0392b',
+}
+
+export function MatchScoreRing({ score, strength, size = 'md', showLabel = true }: MatchScoreRingProps) {
+  const dim = SIZE_MAP[size]
+  const colorKey = matchScoreColor(score)
+  const color = COLOR_MAP[colorKey]
+  const bgColor = colorKey === 'success' ? 'rgba(26,122,74,0.08)' : colorKey === 'warning' ? 'rgba(217,119,6,0.08)' : 'rgba(192,57,43,0.08)'
+
+  return (
+    <Box sx={{ display: 'flex', flexDirection: 'column', alignItems: 'center', gap: 0.5 }}>
+      <Box
+        sx={{
+          width: dim.ring,
+          height: dim.ring,
+          borderRadius: '50%',
+          border: `3px solid ${color}`,
+          bgcolor: bgColor,
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+          flexShrink: 0,
+        }}
+      >
+        <Typography sx={{ fontSize: dim.font, fontWeight: 700, color, lineHeight: 1 }}>
+          {score}
+        </Typography>
+      </Box>
+      {showLabel && (
+        <Typography sx={{ fontSize: dim.label, fontWeight: 600, color, textTransform: 'uppercase', letterSpacing: '0.06em' }}>
+          {MATCH_STRENGTH_LABELS[strength]}
+        </Typography>
+      )}
+    </Box>
+  )
+}

src/components/scores/index.ts

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+export { MatchScoreRing } from './MatchScoreRing'