feat: Add lightweight Node.js document shim and enhance type checking guards

.replit

@@ -0,0 +1,23 @@
+run = "./run.sh"
+entrypoint = "src/index.ts"
+hidden = [".config", "package-lock.json", "tsconfig.json"]
+modules = ["nodejs-20"]
+
+[nix]
+channel = "stable-24_05"
+
+[gitHubImport]
+requiredFiles = [".replit", "replit.nix", ".config"]
+
+[deployment]
+run = ["./run.sh"]
+deploymentTarget = "cloudrun"
+ignorePorts = false
+
+[[ports]]
+localPort = 3000
+externalPort = 80
+
+[[ports]]
+localPort = 9876
+externalPort = 3000