feat: Pattern Lab — historical backtest engine for pattern discovery

- Remove all built-in patterns (no proof of legitimacy); seed_builtin_patterns is now a no-op
- DB: add backtest_lab_runs table + backtest_hits/runs_count columns on patterns
- services/pattern_lab.py: build_historical_context (yfinance + RSI/MA200),
  run_ai_backtest (GPT-4o as historical analyst), evaluate_outcomes (actual moves at T+horizon)
- routers/pattern_lab.py: POST /run, POST /evaluate/{id}, GET /runs, DELETE /runs/{id},
  POST /save-pattern (promotes hit pattern to library with reliability counters)
- PatternLab.tsx: 34 preset events 2015-2025 (macro/geo/credit/fx/commodities/volatility/tech),
  3-panel layout — preset selector + wizard + run history, market data table,
  AI pattern cards with hit/miss outcome display, Save to Library button
- useApi.ts: usePatternLabRuns, useRunPatternLab, useEvaluatePatternLab, useSaveLabPattern, useDeleteLabRun
- Sidebar + App.tsx: /pattern-lab route + FlaskConical nav link

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

frontend/src/hooks/useApi.ts

@@ -958,3 +958,52 @@ export const useRefreshInstitutionalReports = () =>
     mutationFn: (report_type?: string) =>
       api.post('/institutional/refresh', null, { params: report_type ? { report_type } : {} }).then(r => r.data),
   })
+
+// ── Pattern Lab ───────────────────────────────────────────────────────────────
+export const usePatternLabRuns = () =>
+  useQuery({
+    queryKey: ['pattern-lab-runs'],
+    queryFn: () => api.get('/pattern-lab/runs').then(r => r.data),
+    staleTime: 30_000,
+  })
+
+export const useRunPatternLab = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (body: {
+      preset_id?: string; theme: string; analysis_date: string;
+      horizon_days: number; assets: string[]; theme_hint: string;
+    }) => api.post('/pattern-lab/run', body).then(r => r.data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['pattern-lab-runs'] }),
+  })
+}
+
+export const useEvaluatePatternLab = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (run_id: string) => api.post(`/pattern-lab/evaluate/${run_id}`, {}).then(r => r.data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['pattern-lab-runs'] }),
+  })
+}
+
+export const useSaveLabPattern = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (body: {
+      run_id: string; pattern_index: number; name?: string;
+      category?: string; signal_direction?: string; asset_class?: string;
+    }) => api.post('/pattern-lab/save-pattern', body).then(r => r.data),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['all-patterns'] })
+      qc.invalidateQueries({ queryKey: ['pattern-lab-runs'] })
+    },
+  })
+}
+
+export const useDeleteLabRun = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: (run_id: string) => api.delete(`/pattern-lab/runs/${run_id}`).then(r => r.data),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ['pattern-lab-runs'] }),
+  })
+}