Add some types and a basic test to the SDK (#4472)

sdk/typescript/jest.config.cjs

@@ -0,0 +1,16 @@
+/** @type {import('jest').Config} */
+module.exports = {
+  preset: "ts-jest/presets/default-esm",
+  testEnvironment: "node",
+  extensionsToTreatAsEsm: [".ts"],
+  globals: {
+    "ts-jest": {
+      useESM: true,
+      tsconfig: "tsconfig.json",
+    },
+  },
+  moduleNameMapper: {
+    "^(\\.{1,2}/.*)\\.js$": "$1",
+  },
+  testMatch: ["**/tests/**/*.test.ts"],
+};