fix: set render concurrency to 1

src/render.ts

@@ -16,7 +16,9 @@ const COMPOSITION_ID = 'VEditor';
 
 // Configuration
 const CONFIG = {
-    concurrency: Math.max(1, Math.floor(os.cpus().length / 2)),
+    // Set concurrency to 1 to ensure stability in container environments
+    // os.cpus() can report host cores which are not accessible
+    concurrency: 1,
     verbose: false,
     timeoutMs: 300000, // 5 minutes
 };