feat: Organisateur IA — analyse carnet + tags + doublons + regroupements

- Service notebook-organizer.service.ts : analyse IA des notes
- Endpoint /api/ai/organize-notebook
- Dialog avec 4 sections :
  1. Résumé de l'état du carnet
  2. Tags suggérés (cliquable pour appliquer)
  3. Regroupements logiques par catégorie
  4. Détection de doublons avec explication
- Bouton 'Organiser' (Wand2) dans la barre du carnet
- i18n FR/EN complet
- Complète les 3 scénarios : Prof (wizard+exercices), Étudiant (wizard+planning), Ingénieur (organisateur)

memento-note/locales/en.json

@@ -2575,6 +2575,16 @@
     "wizardStudyPlanSuccess": "Plan created! Reminders have been added to your notes.",
     "wizardDaysPlanned": "days planned",
     "wizardStudyPlanReminders": "Reminders have been automatically added to your notes.",
+    "wizardOrganizer": "Organize with AI",
+    "wizardOrganizerDesc": "AI analyzes your notes and suggests tags, groupings and duplicate detection.",
+    "wizardAnalyze": "Analyze notebook",
+    "wizardOrganizing": "Analyzing notes...",
+    "wizardSuggestedTags": "Suggested tags",
+    "wizardCategories": "Suggested groupings",
+    "wizardDuplicates": "Duplicates detected",
+    "wizardApply": "Apply",
+    "wizardTagApplied": "applied",
+    "wizardNoSuggestions": "No suggestions — notebook looks well organized.",
     "importMarkdown": "Import Markdown",
     "markdownExportSuccess": "Note exported as Markdown",
     "markdownExportError": "Failed to export note",