Harden gameplay timing and map loading

tests/service-error.test.ts

@@ -0,0 +1,18 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { checkServiceError, ServiceError } from "../lib/service-error";
+
+test("backend failures use 503 and keep database internals out of browser errors", (t) => {
+  t.mock.method(console, "error", () => {});
+  assert.throws(() => checkServiceError({ code: "42P01", message: 'relation "private_table" does not exist' }), (error) => {
+    assert.ok(error instanceof ServiceError);
+    assert.equal(error.status, 503);
+    assert.doesNotMatch(error.message, /private_table|42P01/);
+    return true;
+  });
+});
+test("missing records and expected RPC validation keep actionable statuses and messages", () => {
+  assert.throws(() => checkServiceError({ code: "PGRST116", message: "no rows" }), (error) => error instanceof ServiceError && error.status === 404);
+  assert.throws(() => checkServiceError({ code: "P0001", message: "Guess outside map" }), /Guess outside map/);
+  assert.doesNotThrow(() => checkServiceError(null));
+});