Fix postinstall patches for partial workspace installs

scripts/postinstall-patches.mjs

@@ -0,0 +1,14 @@
+import { existsSync } from "node:fs";
+import { spawnSync } from "node:child_process";
+
+// In CI we often install a single workspace (e.g. server/relay/website). Only apply patches
+// when the patched dependency is actually present.
+const hasDraggableFlatlist = existsSync("node_modules/react-native-draggable-flatlist");
+if (!hasDraggableFlatlist) {
+  process.exit(0);
+}
+
+const cmd = process.platform === "win32" ? "patch-package.cmd" : "patch-package";
+const result = spawnSync(cmd, { stdio: "inherit" });
+process.exit(result.status ?? 1);
+