feat: auto-save 2s + indicateur save + reminders inline actions (compléter/snooze)

- Auto-save debounce 2s dans note-editor-context
- lastSavedAt state + setIsDirty(false) dans handleSave
- Indicateur toolbar: ✓ sauvegardé / ● non enregistré avec timer relatif
- Reminders sidebar: bouton ✓ compléter + bouton +1h snooze (hover inline)
- i18n: clés reminders.markDone/snooze1h + notes.savedJustNow/unsaved (15 locales)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

memento-note/components/note-editor/note-editor-toolbar.tsx

@@ -1,6 +1,6 @@
 'use client'
 
-import { useState, useRef, useCallback } from 'react'
+import { useState, useRef, useCallback, useEffect } from 'react'
 import { useNoteEditorContext } from './note-editor-context'
 import { LabelManager } from '@/components/label-manager'
 import { LabelBadge } from '@/components/label-badge'
@@ -46,6 +46,21 @@ export function NoteEditorToolbar({ mode, onClose, onToggleAttachments, attachme
   const [isConverting, setIsConverting] = useState(false)
   const [shareOpen, setShareOpen] = useState(false)
   const [flashcardsOpen, setFlashcardsOpen] = useState(false)
+  const [relativeTime, setRelativeTime] = useState<string | null>(null)
+
+  // Mise à jour du temps relatif depuis la dernière sauvegarde
+  useEffect(() => {
+    if (!state.lastSavedAt) { setRelativeTime(null); return }
+    const update = () => {
+      const secs = Math.floor((Date.now() - state.lastSavedAt!.getTime()) / 1000)
+      if (secs < 10) setRelativeTime(t('notes.savedJustNow') || 'Sauvegardé')
+      else if (secs < 60) setRelativeTime(`${secs}s`)
+      else setRelativeTime(`${Math.floor(secs / 60)}min`)
+    }
+    update()
+    const interval = setInterval(update, 10000)
+    return () => clearInterval(interval)
+  }, [state.lastSavedAt, t])
 
   const notebookName = notebooks.find(nb => nb.id === note.notebookId)?.name || null
 
@@ -294,20 +309,34 @@ export function NoteEditorToolbar({ mode, onClose, onToggleAttachments, attachme
           )}
 
           {!readOnly && (
-            <button
-              title={state.isDirty ? t('notes.saveNow') : t('notes.noModification')}
-              aria-label={state.isDirty ? t('notes.saveNoteAria') : t('notes.noChangesToSaveAria')}
-              onClick={actions.handleSaveInPlace}
-              disabled={state.isSaving || !state.isDirty}
-              className={cn(
-                'p-1.5 rounded-full border transition-all duration-300',
-                state.isDirty
-                  ? 'bg-foreground text-background border-foreground hover:opacity-80'
-                  : 'border-black/20 dark:border-white/20 text-foreground/40 cursor-not-allowed'
+            <div className="flex items-center gap-1.5">
+              {/* Indicateur dernière sauvegarde */}
+              {!state.isDirty && relativeTime && !state.isSaving && (
+                <span className="hidden sm:flex items-center gap-1 text-[10px] text-concrete/70 font-medium select-none">
+                  <Check size={10} className="text-emerald-500" />
+                  {relativeTime}
+                </span>
               )}
-            >
-              {state.isSaving ? <Loader2 size={14} className="animate-spin" /> : <Save size={14} />}
-            </button>
+              {state.isDirty && !state.isSaving && (
+                <span className="hidden sm:block text-[10px] text-amber-500 font-medium select-none">
+                  {t('notes.unsaved') || '●'}
+                </span>
+              )}
+              <button
+                title={state.isDirty ? t('notes.saveNow') : t('notes.noModification')}
+                aria-label={state.isDirty ? t('notes.saveNoteAria') : t('notes.noChangesToSaveAria')}
+                onClick={actions.handleSaveInPlace}
+                disabled={state.isSaving || !state.isDirty}
+                className={cn(
+                  'p-1.5 rounded-full border transition-all duration-300',
+                  state.isDirty
+                    ? 'bg-foreground text-background border-foreground hover:opacity-80'
+                    : 'border-black/20 dark:border-white/20 text-foreground/40 cursor-not-allowed'
+                )}
+              >
+                {state.isSaving ? <Loader2 size={14} className="animate-spin" /> : <Save size={14} />}
+              </button>
+            </div>
           )}
 
           {!readOnly && (