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/main.tsx

@@ -4,13 +4,15 @@ import { BrowserRouter } from 'react-router'
 import { StyledEngineProvider, ThemeProvider, CssBaseline } from '@mui/material'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { theme } from './lib/theme'
+import { AuthProvider } from './provider/AuthProvider'
+import { STALE_PROPERTIES } from './lib/constants'
 import './index.css'
 import App from './App.tsx'
 
 const queryClient = new QueryClient({
   defaultOptions: {
     queries: {
-      staleTime: 5 * 60 * 1000,
+      staleTime: STALE_PROPERTIES,
       retry: 1,
     },
   },
@@ -23,7 +25,9 @@ createRoot(document.getElementById('root')!).render(
         <StyledEngineProvider injectFirst>
           <ThemeProvider theme={theme}>
             <CssBaseline />
-            <App />
+            <AuthProvider>
+              <App />
+            </AuthProvider>
           </ThemeProvider>
         </StyledEngineProvider>
       </QueryClientProvider>