fix(audit): sécurité + perf + DB — 40 problèmes adressés

SÉCURITÉ (CRITIQUE):
- link-preview: auth() obligatoire + filtre IP privées (SSRF fix)
- metrics: !metricsToken → 401 au lieu d'etre ouvert si token absent
- contextual-ai-chat: DOMPurify.sanitize() sur dangerouslySetInnerHTML (XSS fix)

PERFORMANCE:
- graph/route.ts: take:500 + orderBy updatedAt desc (pas de full table scan)
- syncAllEmbeddings: batch parallèle Promise.allSettled × 5 (pas séquentiel)
- 80 console.log supprimés du code production

BASE DE DONNÉES:
- Note: index contentUpdatedAt + isPublic ajoutés au schema
- DocumentChunk: commentaire index vectoriel HNSW (à exécuter manuellement)

memento-note/app/actions/organize-notebook.ts

@@ -205,7 +205,6 @@ export async function executeNotebookOrganization(plan: OrganizationPlan): Promi
     })
     if (!notebook) return { success: false, created: 0, moved: 0, error: 'Carnet introuvable' }
 
-    console.log('[organize-notebook] Executing plan:', JSON.stringify({
       notebookId: plan.notebookId,
       groups: plan.groups.map(g => ({ name: g.name, isNew: g.isNew, existingId: g.existingId, noteCount: g.notes.length }))
     }))
@@ -254,7 +253,6 @@ export async function executeNotebookOrganization(plan: OrganizationPlan): Promi
             userId: session.user.id,
           },
         })
-        console.log(`[organize-notebook] Created sub-notebook "${newSub.name}" (id: ${newSub.id}) under ${plan.notebookId}`)
         targetNotebookId = newSub.id
         created++
       }
@@ -269,7 +267,6 @@ export async function executeNotebookOrganization(plan: OrganizationPlan): Promi
           },
           data: { notebookId: targetNotebookId },
         })
-        console.log(`[organize-notebook] Moved ${result.count} notes to "${group.name}"`)
         moved += result.count
       }
     }