Tighten YuE lyrics validation and Comfy music workflow wiring.

Require section tags before queueing YuE and keep the ACE/YuE path changes that were already in progress.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/utils/comfy.ts

@@ -195,6 +195,16 @@ export async function interruptComfy() {
   return Boolean(res?.ok)
 }
 
+/** Ask Comfy to drop cached models so a heavy YuE job starts with a clean 16GB card. */
+export async function freeComfyVram() {
+  await comfyFetch('/free', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ unload_models: true, free_memory: true }),
+    signal: AbortSignal.timeout(15000)
+  }).catch(() => null)
+}
+
 export async function fetchHistory(promptId: string) {
   const res = await comfyFetch(`/history/${encodeURIComponent(promptId)}`)
   if (!res.ok) return null