fix: PatternLab save UX — color-coded toasts + meaningful error feedback

- handleSave now shows a red toast "Lancez d'abord un backtest" instead of
  silently returning when activeRun is null (was completely invisible to user)
- All toasts now color-coded: green (emerald) for success, red for errors
- list_runs now includes context_snapshot so market data table shows when
  loading a historical run from the right panel

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

backend/routers/pattern_lab.py

@@ -168,7 +168,7 @@ def list_runs():
     conn = get_conn()
     rows = conn.execute("""SELECT id, preset_id, theme, analysis_date, horizon_days,
         assets, status, created_at, evaluated_at,
-        outcome, ai_result
+        outcome, ai_result, context_snapshot
         FROM backtest_lab_runs ORDER BY created_at DESC LIMIT 100""").fetchall()
     conn.close()
     return [_row_to_dict(r) for r in rows]

frontend/src/pages/PatternLab.tsx

@@ -296,7 +296,7 @@ export default function PatternLab() {
   // ── Current run state (events mode)
   const [activeRun, setActiveRun]   = useState<any | null>(null)
   const [savedIdx, setSavedIdx]     = useState<Set<number>>(new Set())
-  const [toast, setToast]           = useState<string | null>(null)
+  const [toast, setToast]           = useState<{ msg: string; type: 'ok' | 'err' } | null>(null)
   const [matchResults, setMatchResults] = useState<Record<string, MatchResult>>({})
   const [matchLoading, setMatchLoading] = useState<Record<string, boolean>>({})
 
@@ -307,9 +307,9 @@ export default function PatternLab() {
     return true
   }), [search, yearFilter, catFilter])
 
-  const showToast = (msg: string) => {
+  const showToast = (msg: string, type: 'ok' | 'err' = 'ok') => {
-    setToast(msg)
+    setToast({ msg, type })
-    setTimeout(() => setToast(null), 3000)
+    setTimeout(() => setToast(null), 4000)
   }
 
   const handleSelectPreset = (p: Preset) => {
@@ -344,7 +344,7 @@ export default function PatternLab() {
       const res = await discoverEvents({ query: discoverQuery.trim(), n: 6 })
       setDiscoverResults(res.events)
     } catch (e: any) {
-      showToast(`Discover failed: ${e?.response?.data?.detail ?? e?.message}`)
+      showToast(`Discover failed: ${e?.response?.data?.detail ?? e?.message}`, 'err')
     }
   }
 
@@ -363,7 +363,7 @@ export default function PatternLab() {
       setActiveRun(result)
       setSavedIdx(new Set())
     } catch (e: any) {
-      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`)
+      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`, 'err')
     }
   }
 
@@ -373,7 +373,7 @@ export default function PatternLab() {
       const result = await evaluateRun(activeRun.run_id)
       setActiveRun((prev: any) => ({ ...prev, outcome: result.outcomes }))
     } catch (e: any) {
-      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`)
+      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`, 'err')
     }
   }
 
@@ -387,7 +387,7 @@ export default function PatternLab() {
       const result = await findMatching({ run_id: activeRun.run_id, pattern_index: idx })
       setMatchResults(prev => ({ ...prev, [key]: result }))
     } catch (e: any) {
-      showToast(`Find matching failed: ${e?.response?.data?.detail ?? e?.message}`)
+      showToast(`Find matching failed: ${e?.response?.data?.detail ?? e?.message}`, 'err')
     } finally {
       setMatchLoading(prev => ({ ...prev, [key]: false }))
     }
@@ -399,7 +399,10 @@ export default function PatternLab() {
     target_id?: string,
     regime_tag?: string,
   ) => {
-    if (!activeRun?.run_id) return
+    if (!activeRun?.run_id) {
+      showToast('Lancez d\'abord un backtest (bouton Run)', 'err')
+      return
+    }
     const pat = activeRun.ai_result?.patterns?.[idx]
     if (!pat) return
     try {
@@ -415,9 +418,9 @@ export default function PatternLab() {
       })
       setSavedIdx(prev => new Set([...prev, idx]))
       const actionLabel = action === 'instance' ? 'merged as instance' : action === 'counter' ? 'saved as counter-scenario' : 'saved'
-      showToast(`"${pat.name}" ${actionLabel}`)
+      showToast(`"${pat.name}" ${actionLabel}`, 'ok')
     } catch (e: any) {
-      showToast(`Save failed: ${e?.response?.data?.detail ?? e?.message}`)
+      showToast(`Save failed: ${e?.response?.data?.detail ?? e?.message}`, 'err')
     }
   }
 
@@ -442,7 +445,7 @@ export default function PatternLab() {
       const result = await evaluateInst(instRun.run_id)
       setInstRun((prev: any) => ({ ...prev, outcome: result.outcomes }))
     } catch (e: any) {
-      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`)
+      showToast(`Error: ${e?.response?.data?.detail ?? e?.message ?? 'unknown'}`, 'err')
     }
   }
 
@@ -453,9 +456,9 @@ export default function PatternLab() {
     try {
       await savePattern({ run_id: instRun.run_id, pattern_index: idx, name: pat.name, category: pat.category, signal_direction: pat.signal_direction })
       setInstSavedIdx(prev => new Set([...prev, idx]))
-      showToast(`"${pat.name}" saved to Pattern Library`)
+      showToast(`"${pat.name}" saved to Pattern Library`, 'ok')
     } catch (e: any) {
-      showToast(`Save failed: ${e?.response?.data?.detail ?? e?.message}`)
+      showToast(`Save failed: ${e?.response?.data?.detail ?? e?.message}`, 'err')
     }
   }
 
@@ -1089,10 +1092,10 @@ export default function PatternLab() {
                 setEditAssets((Array.isArray(run.assets) ? run.assets : []).join(', '))
                 setEditHint(run.theme_hint ?? '')
                 setActiveRun({
-                  run_id: run.id,
+                  run_id:    run.id,
-                  context: run.context_snapshot,
+                  context:   run.context_snapshot,
                   ai_result: run.ai_result,
-                  outcome: run.outcome,
+                  outcome:   run.outcome,
                 })
                 setSavedIdx(new Set())
                 setMatchResults({})
@@ -1135,8 +1138,13 @@ export default function PatternLab() {
 
       {/* ── Toast ── */}
       {toast && (
-        <div className="fixed bottom-5 left-1/2 -translate-x-1/2 bg-slate-800 border border-slate-600 rounded-lg px-4 py-2 text-sm text-slate-200 shadow-xl z-50">
+        <div className={clsx(
-          {toast}
+          'fixed bottom-5 left-1/2 -translate-x-1/2 rounded-lg px-4 py-2 text-sm shadow-xl z-50 border',
+          toast.type === 'ok'
+            ? 'bg-emerald-900/90 border-emerald-600 text-emerald-100'
+            : 'bg-red-900/90 border-red-600 text-red-100'
+        )}>
+          {toast.msg}
         </div>
       )}
     </div>