fix(sync): WL diagnostic, import-all paginé + totaux, sync auto historique InnerTube

- Watch Later: youtube_no_channel / watchlater_not_found avec hint
  actionnable + log cles relatedPlaylists (sans PII)
- Preview Google: totaux compte (subscriptionTotal/likeTotal), UI
  'X / N, l'import prend tout'; import-all paginé (subs<=1000,
  likes<=500) au lieu de 50/25
- Sync auto historique: GET /oauth/google/yt-history (browse FEhistory
  authentifie, continuations, <=500), bouton Sync auto dans carte
  Takeout, import via lots takeout existants

server/index.mjs

@@ -105,7 +105,7 @@ import {
   oauthStatus, buildAuthUrl, createOAuthState, consumeOAuthState, exchangeCode,
   refreshAccessToken, redirectUriFor, fetchGoogleProfile, fetchGoogleSubscriptions,
   fetchGoogleLiked, fetchTwitchProfile, fetchTwitchFollows, hasGoogleWriteScope,
-  fetchGoogleWatchLater, pushGoogleWatchLater,
+  fetchGoogleWatchLater, pushGoogleWatchLater, fetchInnerTubeHistory,
 } from './oauth.mjs';
 import { getSearchMode, getYtDlpBin, hasCookiesFile, metricsSnapshot } from './providers/youtube-common.mjs';
 import { ytScrapeCacheStats } from './providers/youtube.mjs';
@@ -564,11 +564,20 @@ r.get('/oauth/:provider/preview', authMiddlewareCookieAware, oauthLimiter, async
     const provider = requireOAuthProvider(req.params.provider);
     const conn = await freshOAuthToken(req.user.id, provider);
     if (provider === 'google') {
-      const [subscriptions, likes] = await Promise.all([
-        fetchGoogleSubscriptions(conn.accessToken, 50).catch(() => []),
-        fetchGoogleLiked(conn.accessToken, 25).catch(() => []),
+      const [subsRes, likesRes] = await Promise.all([
+        fetchGoogleSubscriptions(conn.accessToken, 50).catch(() => ({ items: [], total: 0 })),
+        fetchGoogleLiked(conn.accessToken, 25).catch(() => ({ items: [], total: 0 })),
       ]);
-      return res.json({ provider, subscriptions, likes, subscriptionCount: subscriptions.length, likeCount: likes.length });
+      return res.json({
+        provider,
+        subscriptions: subsRes.items,
+        likes: likesRes.items,
+        subscriptionCount: subsRes.items.length,
+        likeCount: likesRes.items.length,
+        // Totaux du compte (l'aperçu n'affiche que les 50/25 premiers, l'import prend tout).
+        subscriptionTotal: subsRes.total,
+        likeTotal: likesRes.total,
+      });
     }
     const profile = await fetchTwitchProfile(conn.accessToken).catch(() => ({ id: conn.externalUserId || '' }));
     const follows = await fetchTwitchFollows(conn.accessToken, profile?.id || conn.externalUserId || '', 100);
@@ -594,7 +603,8 @@ r.post('/oauth/:provider/import', authMiddlewareCookieAware, oauthLimiter, async
 
     if (provider === 'google') {
       if (wantSubs) {
-        const subs = await fetchGoogleSubscriptions(conn.accessToken, 50);
+        // Import complet paginé (l'aperçu n'en montre que 50).
+        const { items: subs } = await fetchGoogleSubscriptions(conn.accessToken, 1000);
         for (const s of subs) {
           try {
             const row = upsertChannelRow({
@@ -608,7 +618,8 @@ r.post('/oauth/:provider/import', authMiddlewareCookieAware, oauthLimiter, async
         }
       }
       if (wantLikes) {
-        const likes = await fetchGoogleLiked(conn.accessToken, 25);
+        // Import complet paginé (l'aperçu n'en montre que 25).
+        const { items: likes } = await fetchGoogleLiked(conn.accessToken, 500);
         for (const v of likes) {
           try {
             likeVideo({ userId: req.user.id, provider: 'youtube', videoId: v.videoId, title: v.title, thumbnail: v.thumbnail });
@@ -655,7 +666,47 @@ r.get('/oauth/google/watchlater', authMiddlewareCookieAware, oauthLimiter, async
       writeGranted: hasGoogleWriteScope(conn.scopes),
     });
   } catch (error) {
-    return res.status(error?.status || 502).json({ error: error?.message || 'watchlater_fetch_failed' });
+    const out = { error: error?.message || 'watchlater_fetch_failed' };
+    if (error?.hint) out.hint = error.hint;
+    return res.status(error?.status || 502).json(out);
+  }
+});
+
+// -------------------- Google : historique auto via InnerTube authentifié --------------------
+// L'API Data v3 n'expose pas l'historique : on lit youtubei/v1/browse
+// (FEhistory) avec le Bearer OAuth de l'utilisateur (mécanisme SmartTube).
+// Le client réutilise ensuite POST /user/history/takeout pour l'importer.
+
+function innertubeApiKey() {
+  const single = String(process.env.YOUTUBE_API_KEY || '').trim();
+  if (single && !single.includes(',')) return single;
+  const csv = String(process.env.YOUTUBE_API_KEYS || '').trim();
+  try {
+    if (csv.startsWith('[')) {
+      const arr = JSON.parse(csv);
+      if (Array.isArray(arr) && arr[0]) return String(arr[0]);
+    }
+  } catch {}
+  if (csv) {
+    const first = csv.split(',').map((s) => s.trim()).filter(Boolean)[0];
+    if (first) return first;
+  }
+  if (single) return single.split(',').map((s) => s.trim()).filter(Boolean)[0] || '';
+  return '';
+}
+
+r.get('/oauth/google/yt-history', authMiddlewareCookieAware, oauthLimiter, async (req, res) => {
+  try {
+    const conn = await freshOAuthToken(req.user.id, 'google');
+    const max = Math.min(500, Math.max(1, Number(req.query.max || 200)));
+    const { items, hasMore } = await fetchInnerTubeHistory(conn.accessToken, innertubeApiKey(), max);
+    return res.json({ items, count: items.length, hasMore });
+  } catch (error) {
+    const out = { error: error?.message || 'ythistory_fetch_failed' };
+    if (error?.status === 401) {
+      out.hint = 'Session Google expirée : déconnectez puis reconnectez Google.';
+    }
+    return res.status(error?.status || 502).json(out);
   }
 });