refactor(notes): extract title validation into domain service

src/components/NoteEditor.tsx

@@ -3,6 +3,7 @@ import type {
   NoteEditorProps,
   NoteFormProps,
 } from '../interfaces/note-editor'
+import { isTitleValid, normalizeTitle } from '../lib/noteValidation'
 import DeleteModal from './DeleteModal'
 
 const TITLE_REQUIRED_MESSAGE = 'Le titre est obligatoire.'
@@ -82,15 +83,15 @@ function NoteEditor(props: NoteEditorProps) {
 
   const handleTitleChange = (value: string) => {
     setTitle(value)
-    if (titleMissing && value.trim() !== '') setTitleMissing(false)
+    if (titleMissing && isTitleValid(value)) setTitleMissing(false)
   }
 
   const handleSubmit = () => {
-    if (title.trim() === '') {
+    if (!isTitleValid(title)) {
       setTitleMissing(true)
       return
     }
-    const safeTitle = title.trim()
+    const safeTitle = normalizeTitle(title)
     if (props.mode === 'create') {
       props.onCreate(safeTitle, content)
     } else {