Add layout API routes (list/save/load/delete)

server/server.js

@@ -79,6 +79,27 @@ app.put('/api/scene', guard, (req, res) => {
 });
 app.post('/api/scene/reset', guard, (req, res) => res.json(state.resetToSeed()));
 
+// ---------- named layouts (scene + its playlist) ----------
+app.get('/api/layouts', (req, res) => res.json(state.listLayouts()));
+app.post('/api/layouts', guard, (req, res) => {
+  try {
+    const name = (req.body && req.body.name || '').trim();
+    if (!name) return res.status(400).json({ error: 'name required' });
+    res.json(state.saveLayout(name, playlist.getConfig()));
+  } catch (e) { res.status(400).json({ error: String(e.message || e) }); }
+});
+app.post('/api/layouts/:slug/load', guard, (req, res) => {
+  try {
+    const { scene, playlist: pl } = state.loadLayout(req.params.slug);
+    if (pl) playlist.reloadFromState();
+    res.json({ scene, layouts: state.listLayouts() });
+  } catch (e) { res.status(400).json({ error: String(e.message || e) }); }
+});
+app.delete('/api/layouts/:slug', guard, (req, res) => {
+  try { res.json(state.deleteLayout(req.params.slug)); }
+  catch (e) { res.status(400).json({ error: String(e.message || e) }); }
+});
+
 // ---------- playlist config ----------
 app.get('/api/playlist', (req, res) => res.json(playlist.getConfig()));
 app.put('/api/playlist', guard, (req, res) => {