Defer to @tsconfig settings for module

The "module" setting is defined in the base tsconfig.json that we're
using, and overriding it actually resulted in a mismatch with the
latest `moduleResolution` that was being defined in that base.

The `Node16` setting appears to simply signal *support* for ESM
depending on the `type` setting in `package.json`.  This is based on the
ECMAScript Modules in Node.js documentation[1] as well as the TS
configuration documentation[2].

I've added `"type": "commonjs"` to `package.json` although the omitted
setting defaulted to `commonjs` which means this change is just to make
the setting explicit.

[1] https://www.typescriptlang.org/docs/handbook/esm-node.html
[2] https://www.typescriptlang.org/tsconfig#node16nodenext-nightly-builds

package.json

@@ -41,6 +41,7 @@
   "engines": {
     "node": "18"
   },
+  "type": "commonjs",
   "devDependencies": {
     "@tsconfig/node18": "^18.2.1",
     "@types/cors": "^2.8.13",

tsconfig.json

@@ -1,7 +1,6 @@
 {
   "extends": "@tsconfig/node18/tsconfig.json",
   "compilerOptions": {
-    "module": "commonjs",
     "outDir": "dist",
     "declaration": true,
     "esModuleInterop": true,