feat: blocs Callout (encadrés colorés) + Outline (sommaire auto)

- Callout : 5 types (info, alerte, astuce, succès, danger), icône cliquable pour changer de type, unwrap + supprimer, i18n FR/EN
- Outline : table des matières auto-générée depuis H1/H2/H3, design hiérarchique (disque/cercle/point), cliquable pour naviguer, i18n FR/EN
- Accessibles depuis slash menu + drag handle
- Raccourcis: Mod+Shift+C (callout), Mod+Shift+O (outline)

memento-note/locales/en.json

@@ -2409,6 +2409,21 @@
     "slashDatabaseDesc": "Embed your notebook's structured data",
     "slashToggle": "Toggle Section",
     "slashToggleDesc": "Create a collapsible section",
+    "slashCallout": "Callout",
+    "slashCalloutDesc": "Highlight text (info, warning, tip)",
+    "slashOutline": "Table of Contents",
+    "slashOutlineDesc": "Auto-generated outline from your headings",
+    "outlineTitle": "Outline",
+    "outlineEmpty": "Add headings (H1, H2, H3) to generate the outline",
+    "outlineDelete": "Delete outline",
+    "calloutDelete": "Delete callout",
+    "calloutUnwrap": "Disable callout",
+    "calloutInfo": "Information",
+    "calloutWarning": "Warning",
+    "calloutTip": "Tip",
+    "calloutSuccess": "Success",
+    "calloutDanger": "Danger",
+    "blockActionInsertCallout": "Turn into callout",
     "toggleOpened": "Expanded section — click to collapse",
     "toggleClosed": "Collapsed section — click to expand",
     "toggleDelete": "Delete section",