chore(contented): use contented.config.mjs as default (#538)

#### What this PR does / why we need it:

So that projects can use mjs.

packages/contented-example/docs/01-index.md

@@ -3,7 +3,7 @@
 [Contented](https://contented.dev) is a Markdown-based authoring workflow that encourage developer authoring within
 its contextual Git repository. `npm i @contentedjs/contented`
 
-With a headless design of 1 config file `contented.config.js`, developers can start writing
+With a headless design of 1 config file `contented.config.mjs`, developers can start writing
 their [markdown content](04-markdown) and preview it on their localhost `contented write`. Choosing convention over
 configuration reduces HTML/UI clutter, allowing developers to focus on authoring.
 
@@ -58,7 +58,7 @@ repo/
 │  │  ├─ 02:overview.md
 │  │  └─ 03:faq.md
 │  └─ package.json
-├─ contented.config.js
+├─ contented.config.mjs
 ├─ package.json
 └─ README.md
 ```
@@ -83,11 +83,11 @@ repo/
 }
 ```
 
-**contented.config.js**
+**contented.config.mjs**
 
 ```js
 /** @type {import('@contentedjs/contented').ContentedConfig} */
-module.exports = {
+export default {
   preview: {
     url: 'https://contented.dev',
     name: 'Contented',

packages/contented-example/docs/03-api.md

@@ -25,11 +25,11 @@ configure your `package.json` with these fields:
 }
 ```
 
-**`contented.config.js`:**
+**`contented.config.mjs`:**
 
 ```js
 /** @type {import('@contentedjs/contented').ContentedConfig} */
-module.exports = {
+const config = {
   preview: {
     url: 'https://contented.dev',
     name: 'Contented',
@@ -47,6 +47,8 @@ module.exports = {
     ],
   },
 };
+
+export default config;
 ```
 
 **Netlify TOML:**
@@ -99,7 +101,7 @@ automatically ignore files in your `.gitignore` and `.contentedignore`.
 
 > You should also add a `.gitignore` too with `echo "dist\n.contented" > .gitignore`. (Okay fine! 3 files it is. Ughhhh)
 
-### `contented.config.js`
+### `contented.config.mjs`
 
 ```typescript
 export interface ContentedConfig {

packages/contented-preview/src/errors/PipelineCollectionNotFoundException.js

@@ -1,5 +1,5 @@
 export class PipelineCollectionNotFoundException extends Error {
   constructor(pipelineName){
-    super(`Pipeline type '${pipelineName}' cannot resolve its collection. Please check if contented.config.js is properly configured.`)
+    super(`Pipeline type '${pipelineName}' cannot resolve its collection. Please check if contented.config.mjs is properly configured.`)
   }
 }

packages/contented/src/commands/BaseCommand.ts

@@ -1,3 +1,4 @@
+import { existsSync } from 'node:fs';
 import { join } from 'node:path';
 
 import { Command } from 'clipanion';
@@ -7,8 +8,18 @@ import { ContentedConfig } from '../index.js';
 export abstract class BaseCommand extends Command {
   static paths = [[`build`]];
 
+  /**
+   * Load the configuration file for Contented.
+   * Checks for `contented.config.mjs` or `contented.config.js` in the current working directory.
+   *
+   * @returns {Promise<ContentedConfig>} A promise that resolves to the loaded configuration object.
+   */
   async loadConfig(): Promise<ContentedConfig> {
-    const configPath = join(process.cwd(), 'contented.config.js');
+    let configPath = join(process.cwd(), 'contented.config.mjs');
+    if (!existsSync(configPath)) {
+      configPath = join(process.cwd(), 'contented.config.js');
+    }
+
     // eslint-disable-next-line no-console
     console.log(`Loading config from: ${configPath}`);
     const config = await import(configPath);

turbo.json

@@ -5,7 +5,7 @@
       "cache": false
     },
     "build": {
-      "inputs": ["tsconfig.json", "contented.config.js", "src/**"],
+      "inputs": ["tsconfig.json", "contented.config.mjs", "src/**"],
       "outputs": ["dist/**"],
       "dependsOn": ["^build"]
     },