infra: use node16 moduleResolution

- to support "exports" going forward
- downgraded chai types to match chai vesion. new resolution correctly detected it being an esm-only types being imported from our commonjs repository

package.json

@@ -16,7 +16,7 @@
   },
   "devDependencies": {
     "@ts-tools/node": "^6.1.0",
-    "@types/chai": "^5.0.1",
+    "@types/chai": "^4.3.20",
     "@types/mocha": "^10.0.10",
     "@types/node": "22",
     "@webref/css": "~6.12.15",

pleb.config.mjs

@@ -1,3 +1,6 @@
 export default {
-  pinnedPackages: [{ name: 'chai', reason: 'esm only from v5' }],
+  pinnedPackages: [
+    { name: 'chai', reason: 'esm only from v5' },
+    { name: '@types/chai', reason: 'esm only from v5' },
+  ],
 };

tsconfig.base.json

@@ -25,9 +25,9 @@
     // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
 
     /* Modules */
-    "module": "commonjs",                                /* Specify what module code is generated. */
+    "module": "node16",                                  /* Specify what module code is generated. */
     // "rootDir": "./",                                  /* Specify the root folder within your source files. */
-    "moduleResolution": "node",                          /* Specify how TypeScript looks up a file from a given module specifier. */
+    "moduleResolution": "node16",                        /* Specify how TypeScript looks up a file from a given module specifier. */
     // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
     // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
     // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */