refactor(mock-paymaster): replace wait-port with custom anvil wait script

- Added wait-anvil.ts with configurable URL via ANVIL_RPC env var

- Improved error handling with timeout messaging

- Updated package.json to use new wait script

Author: mouseless0x

mock-verifying-paymaster/package.json

@@ -2,7 +2,7 @@
     "name": "mock-paymaster",
     "private": true,
     "scripts": {
-        "start": "wait-port anvil:8545 && tsx src/index.ts"
+        "start": "tsx src/wait-anvil.ts && tsx src/index.ts"
     },
     "dependencies": {
         "@pimlico/mock-paymaster": "^0.0.6",

mock-verifying-paymaster/src/wait-anvil.ts

@@ -0,0 +1,19 @@
+import waitPort from "wait-port";
+
+const url = new URL(process.env.ANVIL_RPC || "http://anvil:8545");
+
+(async () => {
+	const ok = await waitPort({
+		host: url.hostname,
+		port: parseInt(url.port || "80"),
+		timeout: 10000, // 10s timeout
+		output: "silent",
+	});
+
+	if (!ok) {
+		console.error(`❌ Timed out waiting for ${url.hostname}:${url.port}`);
+		process.exit(1);
+	}
+
+	console.log(`✅ ${url.hostname}:${url.port} is available`);
+})();