feat: instrument model

frontend/src/pages/InstrumentModels.tsx

@@ -985,6 +985,7 @@ function TimelineView({ instrument }: { instrument: string }) {
   const [whatifLoading, setWhatifLoading] = useState(false)
   const [whatifData, setWhatifData] = useState<TimelinePoint[] | null>(null)
   const [importingCal, setImportingCal] = useState(false)
+  const [backfilling,  setBackfilling]  = useState(false)
   const [calMsg, setCalMsg]             = useState<string | null>(null)
   // What-if filters
   const [filterImpact,   setFilterImpact]   = useState<string[]>(['high', 'medium'])
@@ -1510,6 +1511,31 @@ function TimelineView({ instrument }: { instrument: string }) {
                 className="flex items-center gap-1 text-xs text-sky-400 hover:text-sky-300 border border-sky-700/40 rounded px-2 py-0.5 transition-colors disabled:opacity-40">
                 <Activity className="w-3 h-3"/> {importingCal ? '…' : 'Import calendrier'}
               </button>
+              <button
+                disabled={backfilling}
+                onClick={async () => {
+                  setBackfilling(true)
+                  setCalMsg('Backfill en cours (peut prendre 2-3 min)…')
+                  try {
+                    // Backfill from 15 months ago to today to fill the April 2025 gap
+                    const fromDate = new Date()
+                    fromDate.setMonth(fromDate.getMonth() - 15)
+                    const r = await api.post<{weeks_scraped: number, total_upserted: number, weeks_skipped: number}>(
+                      '/instrument-models/ff-calendar/backfill',
+                      { from_date: fromDate.toISOString().slice(0, 10) }
+                    )
+                    setCalMsg(`Backfill OK : ${r.data.total_upserted} events, ${r.data.weeks_scraped} semaines (${r.data.weeks_skipped} déjà remplies)`)
+                  } catch (e: any) {
+                    setCalMsg(`Erreur backfill: ${e?.response?.data?.detail ?? e?.message}`)
+                  } finally {
+                    setBackfilling(false)
+                    setTimeout(() => setCalMsg(null), 8000)
+                  }
+                }}
+                className="flex items-center gap-1 text-xs text-emerald-400 hover:text-emerald-300 border border-emerald-700/40 rounded px-2 py-0.5 transition-colors disabled:opacity-40"
+                title="Scrape ForexFactory pour remplir les données manquantes (avril 2025 → aujourd'hui)">
+                <RefreshCw className="w-3 h-3"/> {backfilling ? '…' : 'Sync historique'}
+              </button>
               <button onClick={() => {
                   // Guidance event : pousse la courbe depuis le début avec absorption lente
                   const simStart  = data[0]?.date ?? new Date().toISOString().slice(0, 10)