feat(insights): UX gap closure — i18n, network graph, recalc panel, toasts

Bugs fixes:
- network-graph.tsx: 2 strings hardcoded FR → props i18n (untitledLabel, resetFocusLabel)
- Panneau recalcul: clés i18n réutilisées avec mauvais sens → nouvelles clés recalcSystem.*
- 13 locales: section insightsView.* complète (67 clés × 13 = 871 traductions)

UX features:
- Hint /insights ≠ /graph (semanticGraphLegend + lien vers /graph)
- Toasts succès/échec/zéro-clusters après analyse (analysisSuccess/Failed/NoClusters)
- État vide différencié: emptyNeedMoreNotes si < 10 notes
- Tips contextuels sections Bridge Notes et Suggestions

Sprint:
- 4 epics marqués done (3,4,5,6 — toutes stories terminées)
- sprint-status.yaml last_updated corrigé

memento-note/app/(main)/insights/page.tsx

@@ -18,7 +18,10 @@ import {
   AlertCircle,
   ChevronRight,
   Database,
+  ArrowRight,
 } from 'lucide-react'
+import { toast } from 'sonner'
+import Link from 'next/link'
 
 interface Note {
   id: string
@@ -199,6 +202,12 @@ export default function InsightsPage() {
 
       if (res.ok) {
         const data = await res.json()
+        const clusterCount = data.clusters?.length || 0
+        if (clusterCount === 0) {
+          toast.info(t('insightsView.analysisNoClusters'))
+        } else {
+          toast.success(t('insightsView.analysisSuccess', { count: clusterCount }))
+        }
         const clustersWithColors = (data.clusters || []).map((c: Cluster, i: number) => ({
           ...c,
           id: c.clusterId.toString(),
@@ -225,6 +234,7 @@ export default function InsightsPage() {
       }
     } catch (error) {
       console.error('Error running analysis:', error)
+      toast.error(t('insightsView.analysisFailed'))
     } finally {
       setIsCalculating(false)
     }
@@ -253,6 +263,12 @@ export default function InsightsPage() {
           <p className="text-[10px] text-concrete tracking-[0.25em] uppercase font-bold">
             {t('insightsView.subtitle')}
           </p>
+          <div className="flex items-center gap-1.5 mt-1.5 text-[10px] text-concrete">
+            <span>{t('insightsView.semanticGraphLegend')}</span>
+            <Link href="/graph" className="inline-flex items-center gap-0.5 text-ochre hover:underline font-medium">
+              {t('insightsView.openGraphMap')} <ArrowRight size={9} />
+            </Link>
+          </div>
         </div>
 
         <div className="flex items-center justify-between sm:justify-end gap-3">
@@ -324,7 +340,9 @@ export default function InsightsPage() {
               {t('insightsView.emptyTitle')}
             </h3>
             <p className="text-sm text-concrete leading-relaxed mb-6">
-              {t('insightsView.emptyDescription')}
+              {embeddingStats && embeddingStats.total < 10
+                ? t('insightsView.emptyNeedMoreNotes', { count: 10 - embeddingStats.total })
+                : t('insightsView.emptyDescription')}
             </p>
             <button
               onClick={performAnalysis}
@@ -378,6 +396,9 @@ export default function InsightsPage() {
               onNoteSelect={handleNoteClick}
               selectedClusterId={selectedClusterId}
               onClusterSelect={setSelectedClusterId}
+              untitledLabel={t('insightsView.unknownNote')}
+              resetFocusLabel={t('insightsView.resetFocus')}
+              fitViewLabel={t('insightsView.fitGraphView')}
             />
           </div>
 
@@ -508,22 +529,22 @@ export default function InsightsPage() {
                   <div className="flex items-center gap-2">
                     <Sliders size={15} className="text-ochre" />
                     <h4 className="text-[11px] font-black uppercase tracking-[0.2em] text-ink dark:text-dark-ink">
-                      {t('insightsView.clusters.title')}
+                      {t('insightsView.recalcSystem.title')}
                     </h4>
                   </div>
                   <span className="flex items-center gap-1 text-[9.5px] font-bold text-emerald-500 uppercase">
-                    <CheckCircle2 size={11} /> {t('insightsView.resync')}
+                    <CheckCircle2 size={11} /> {t('insightsView.recalcSystem.statusSynced')}
                   </span>
                 </div>
                 <div className="grid grid-cols-2 gap-4 pt-1">
                   <div className="space-y-1">
-                    <span className="text-[9px] text-concrete block">{t('insightsView.mapping')}</span>
+                    <span className="text-[9px] text-concrete block">{t('insightsView.recalcSystem.scheduledCron')}</span>
                     <p className="text-xs text-ink dark:text-dark-ink font-semibold flex items-center gap-1.5">
                       <Clock size={12} className="opacity-50" /> 04:00
                     </p>
                   </div>
                   <div className="space-y-1">
-                    <span className="text-[9px] text-concrete block">{t('insightsView.resync')}</span>
+                    <span className="text-[9px] text-concrete block">{t('insightsView.recalcSystem.lastSync')}</span>
                     <p className="text-xs text-ink dark:text-dark-ink font-bold font-mono">
                       {lastSyncTime || '—'}
                     </p>
@@ -613,6 +634,7 @@ export default function InsightsPage() {
                     {t('insightsView.bridgeNotes.title')}
                   </h3>
                 </div>
+                <p className="text-[10px] text-concrete italic px-1 -mt-2 leading-relaxed">{t('insightsView.tipBridgeNotes')}</p>
                 <div className="space-y-3">
                   {bridgeList.map(bridge => (
                     <motion.div
@@ -672,6 +694,7 @@ export default function InsightsPage() {
                     {t('insightsView.suggestions.title')}
                   </h3>
                 </div>
+                <p className="text-[10px] text-concrete italic px-1 -mt-2 leading-relaxed">{t('insightsView.tipSuggestions')}</p>
                 <div className="space-y-4">
                   {suggestions.map(s => (
                     <div