fix(mrt): add exports map with ESM-flavoured type declarations

`moduleResolution: node16`/`nodenext` consumers currently read
`dist/index.d.ts` in a CommonJS context, so named imports/types resolve
incorrectly.

Add an `exports` map that routes types per condition: `import` → a new
`dist/index.d.mts` (read as ESM), `require` → the existing
`dist/index.d.ts`. Runtime resolution is unchanged — both `import` and
`require` `default` point at the existing CJS build (`dist/index.js`),
and a `"module"` condition points at the ESM build so bundlers keep the
tree-shakeable output (matching the existing `module` field; Node
ignores this condition). The `.d.mts` is a second output of the existing
`rollup-plugin-dts` step — no copy step, no new dependency. `"./*"`
preserves deep imports (e.g. `locales`).

Author: markedwards

packages/material-react-table/package.json

@@ -27,6 +27,20 @@
   "main": "dist/index.js",
   "module": "dist/index.esm.js",
   "typings": "dist/index.d.ts",
+  "exports": {
+    ".": {
+      "module": "./dist/index.esm.js",
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.js"
+      },
+      "require": {
+        "types": "./dist/index.d.ts",
+        "default": "./dist/index.js"
+      }
+    },
+    "./*": "./*"
+  },
   "files": [
     "dist",
     "locales",

packages/material-react-table/rollup.config.mjs

@@ -39,7 +39,10 @@ export default [
   },
   {
     input: './dist/types/index.d.ts',
-    output: [{ file: `./${pkg.typings}`, format: 'esm' }],
+    output: [
+      { file: `./${pkg.typings}`, format: 'esm' },
+      { file: './dist/index.d.mts', format: 'esm' },
+    ],
     plugins: [
       del({
         hook: 'buildEnd',