fix(eslint-config-turbo): use module.exports for ESLint v8 compatibility (#10902)

### Description

Fixes #10901

In PR #10794, we changed from `module.exports` to `export default`,
which caused bunchee to generate `exports.default = config` instead of
`module.exports = config` in the CommonJS build.

ESLint v8 with legacy `.eslintrc.*` configuration expects shareable
configs to export directly via `module.exports`. When it encounters
`exports.default`, it interprets `'default'` as an unexpected top-level
configuration property, resulting in the error:

```
Unexpected top-level property "default"
```

### Changes

1. **`packages/eslint-config-turbo/src/index.ts`**
- Reverted from `export default config;` to `module.exports = config;`
- Ensures compiled CommonJS output properly exports the config object
directly

2. **`packages/eslint-config-turbo/package.json`**
- Removed the `module` field (no longer generating ESM for main entry)
- Updated `exports[".'"]` to point both `import` and `require` to the
CommonJS build
- Maintains compatibility while ensuring ESLint v8 can properly load the
configuration

### Why This Fixes The Problem

- **Before**: Using `export default` caused bunchee to generate
`exports.default = config;`
- **After**: Using `module.exports` generates `module.exports = config;`
which is what ESLint v8 expects
- ESLint v9 flat config support is maintained through the separate
`./flat` export path

### Testing Instructions

1. Build the package: `pnpm --filter=eslint-config-turbo build`
2. Run package validation: `pnpm --filter=eslint-config-turbo
package:lint`
3. Run type checking: `pnpm --filter=eslint-config-turbo package:types`
4. Verify compiled output: `cat
packages/eslint-config-turbo/dist/cjs/index.js` (should show
`module.exports = config;`)

All checks pass:
- ✅ `publint --strict`
- ✅ `attw --profile node16 --pack`
- ✅ `pnpm lint`
- ✅ Correct CommonJS output

### Compatibility

- ✅ **ESLint v8 (legacy config)**: Uses `require('eslint-config-turbo')`
- now works correctly
- ✅ **ESLint v9 (flat config)**: Uses `import turboConfig from
'eslint-config-turbo/flat'` - continues to work
- ✅ **Modern bundlers**: Can import from either path

CLOSES TURBO-4861

---------

Co-authored-by: pauloZion <[email protected]>

Author: anthonyshew

packages/eslint-config-turbo/package.json

@@ -32,7 +32,6 @@
   ],
   "main": "./dist/cjs/index.js",
   "types": "./dist/cjs/index.d.ts",
-  "module": "./dist/es/index.mjs",
   "exports": {
     "./flat": {
       "import": {
@@ -46,8 +45,8 @@
     },
     ".": {
       "import": {
-        "types": "./dist/es/index.d.mts",
-        "default": "./dist/es/index.mjs"
+        "types": "./dist/cjs/index.d.ts",
+        "default": "./dist/cjs/index.js"
       },
       "require": {
         "types": "./dist/cjs/index.d.ts",

packages/eslint-config-turbo/src/index.ts

@@ -2,5 +2,4 @@ const config = {
   extends: ["plugin:turbo/recommended"],
 };
 
-// eslint-disable-next-line import/no-default-export -- ESLint convention is a default export
-export default config;
+module.exports = config;