Reordonner morceaux selon PDF, paroles dans les pages, sync player↔chapitres

- Reordonne les songs dans le config YAML selon l'ordre du PDF (01→09, 06 en dernier)
- Met à jour les titres avec les noms du PDF et la numérotation correcte
- Remplace le contenu des 11 pages markdown par les paroles des chansons associées
- Ajoute getChapterForSong() dans useBookData pour la recherche inverse
- Ajoute un watcher dans BookPlayer qui navigue au chapitre quand le morceau change
- Flag _skipSongWatch pour éviter les boucles infinies player↔navigation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/components/book/BookPlayer.vue

@@ -190,7 +190,7 @@ function onViewportScroll() {
   scrollPercent.value = max > 0 ? Math.round((el.scrollTop / max) * 100) : 0
 }
 
-const { init: initBookData, getSongs, getPrimarySong, getPlaylistOrder } = useBookData()
+const { init: initBookData, getSongs, getPrimarySong, getChapterForSong, getPlaylistOrder } = useBookData()
 const audioPlayer = useAudioPlayer()
 const playerStore = usePlayerStore()
 
@@ -300,6 +300,8 @@ async function initReading() {
 }
 
 // ── Navigation ──
+let _skipSongWatch = false
+
 function goToChapter(idx: number) {
   chapterIdx.value = idx
   currentPage.value = 0
@@ -308,9 +310,12 @@ function goToChapter(idx: number) {
   if (isScrollMode.value && viewportEl.value) {
     viewportEl.value.scrollTop = 0
   }
-  // Play chapter song
+  // Play chapter song (skip watcher to avoid loop)
   const song = getPrimarySong(chapters[idx].slug)
-  if (song) audioPlayer.loadAndPlay(song)
+  if (song) {
+    _skipSongWatch = true
+    audioPlayer.loadAndPlay(song)
+  }
 }
 
 function nextChapter() {
@@ -347,7 +352,10 @@ function prevPage() {
     currentPage.value = 0
     showSommaire.value = false
     const song = getPrimarySong(chapters[chapterIdx.value].slug)
-    if (song) audioPlayer.loadAndPlay(song)
+    if (song) {
+      _skipSongWatch = true
+      audioPlayer.loadAndPlay(song)
+    }
     // After content loads, go to last page
     watch(activeChapter, async () => {
       await nextTick()
@@ -417,7 +425,10 @@ watch(isOpen, async (open) => {
     const playlist = getPlaylistOrder()
     if (playlist.length) playerStore.setPlaylist(playlist)
     const first = getSongs().find(s => s.id === 'chanson-01')
-    if (first) audioPlayer.loadAndPlay(first)
+    if (first) {
+      _skipSongWatch = true
+      audioPlayer.loadAndPlay(first)
+    }
     // Start reading directly
     await initReading()
   }
@@ -428,6 +439,25 @@ watch(isOpen, async (open) => {
   }
 })
 
+// ── Sync: when song changes in player, navigate to matching chapter ──
+watch(() => playerStore.currentSong, (song) => {
+  if (!song || !isOpen.value) return
+  if (_skipSongWatch) {
+    _skipSongWatch = false
+    return
+  }
+  const slug = getChapterForSong(song.id)
+  if (!slug) return
+  const idx = chapters.findIndex(ch => ch.slug === slug)
+  if (idx !== -1 && idx !== chapterIdx.value) {
+    chapterIdx.value = idx
+    currentPage.value = 0
+    if (isScrollMode.value && viewportEl.value) {
+      viewportEl.value.scrollTop = 0
+    }
+  }
+})
+
 watch(isOpen, (open) => {
   if (import.meta.client) document.body.style.overflow = open ? 'hidden' : ''
 })