fix: complete the TypeScript 7 tsconfig migration

The first pass left three classes of config that BOTH tsc 5.9 and tsc 7
reject. Each was proven against both compilers before changing:

  TS5090  A `paths` target must be relative once `baseUrl` is gone. The
          first pass skipped the "./" prefix wherever baseUrl pointed at
          the config's own directory, reasoning it was semantically
          equivalent. It is not — without baseUrl a non-relative target
          is rejected outright, by 5.9 as well as 7.

  TS5110  `moduleResolution: node16` requires `module: node16`. The first
          pass mapped commonjs projects to node16 resolution alone, which
          BROKE those configs for the current toolchain. Both are now set.

  TS5102  `downlevelIteration` is also removed in TS7; it was missing from
          the dead-flag list.

Verified: repos that tsc 7 previously refused (base-studio, js-sdk, kv-js)
now report zero config errors on tsc 7 AND tsc 5.9.

Co-authored-by: Hanzo Dev <[email protected]>

config/tsconfig.base.json

@@ -14,7 +14,7 @@
     //
     // [0]: https://babeljs.io/docs/en/babel-preset-typescript
     // [1]: https://node.green
-    "module": "commonjs",
+    "module": "node16",
     "target": "ES2022",
     "moduleResolution": "node16",
 
@@ -60,7 +60,6 @@
     // Emit configuration
     "declaration": false,
     "declarationMap": false,
-    "downlevelIteration": true,
     "importHelpers": true,
     "inlineSources": false,
     "noEmitHelpers": true,