Adding runCLI section to the Playground CLI page (#2583)

## Motivation for the change, related issues
This PR enhances the Playground CLI documentation by introducing a new
major section on `Programmatic Usage with JavaScript`. This new content
details how to control the CLI via the `runCLI` function, which is a key
feature for enabling advanced use cases like automated end-to-end
testing.

In addition to this new content, the PR also includes some minor
improvements to the existing documentation to enhance clarity, correct
typos, and address minor inaccuracies.

Overall, these changes make the documentation more complete and
user-friendly, especially for developers looking to integrate the
Playground CLI into their automated workflows.

---------

Co-authored-by: Adam Zieliński <[email protected]>

Author: fellyph

packages/docs/site/docs/developers/05-local-development/04-wp-playground-cli.md

@@ -20,15 +20,15 @@ The Playground CLI requires Node.js 20.18 or higher, which is the recommended Lo
 
 ## Quickstart
 
-Running the Playground CLI is as simple as go to a command-line and run:
+To run the Playground CLI, open a command line and use the following command:
 
 ```bash
 npx @wp-playground/cli@latest server
 ```
 
 ![Playground CLI in Action](@site/static/img/developers/npx-wp-playground-server.gif)
 
-With the previous command, you only get a fresh WordPress instance to test. Most of the developers want to see their work running. If this is your case, test a plugin or a theme. You can run the CLI on your project folder and run the Playground CLI with the `--auto-mount` flag:
+With the previous command, you only get a fresh WordPress instance to test. Most developers will want to test their own work. To test a plugin or a theme, navigate to your project folder and run the CLI with the `--auto-mount` flag:
 
 ```bash
 cd my-plugin-or-theme-directory
@@ -40,7 +40,7 @@ npx @wp-playground/cli@latest server --auto-mount
 By default, the CLI loads the latest stable version of WordPress and PHP 8.3 due to its improved performance. To specify your preferred versions, you can use the flag `--wp=<version>` and `--php=<version>`:
 
 ```bash
-npx @wp-playground/cli@latest server --wp=6.8 --php=8.4
+npx @wp-playground/cli@latest server --wp=6.8 --php=8.3
 ```
 
 ### Loading Blueprints
@@ -117,8 +117,126 @@ The `server` command supports the following optional arguments:
 
 ## Need some help with the CLI?
 
-With the Playground CLI, you can use the `--help` to get some support about the available commands.
+With the Playground CLI, you can use the `--help` flag to get the full list of available commands and arguments.
 
 ```bash
 npx @wp-playground/cli@latest --help
 ```
+
+## Programmatic Usage with JavaScript
+
+The Playground CLI can also be controlled programmatically from your JavaScript/TypeScript code using the `runCLI` function. This gives you direct access to all CLI functionalities within your code, which is useful for automating end-to-end tests. Let's cover the basics of using `runCLI`.
+
+### Running a WordPress instance with a specific version
+
+Using the `runCLI` function, you can specify options like the PHP and WordPress versions. In the example below, we request PHP 8.3, the latest version of WordPress, and to be automatically logged in. All supported arguments are defined in the `RunCLIArgs` type.
+
+```TypeScript
+import { runCLI, RunCLIArgs, RunCLIServer } from "@wp-playground/cli";
+
+let cliServer: RunCLIServer;
+
+cliServer = await runCLI({
+    command: 'server',
+    php: '8.3',
+    wp: 'latest',
+    login: true
+} as RunCLIArgs);
+```
+
+To execute the code above, the developer can set their preferred method. A simple way to execute this code is to save it as a `.ts` file and run it with a tool like `tsx`. For example: `tsx my-script.ts`
+
+### Setting a Blueprint
+
+You can provide a blueprint in two ways: either as an object literal directly passed to the `blueprint` property, or as a string containing the path to an external `.json` file.
+
+```TypeScript
+import { runCLI, RunCLIServer } from "@wp-playground/cli";
+
+let cliServer: RunCLIServer;
+
+cliServer = await runCLI({
+  command: 'server',
+  wp: 'latest',
+  blueprint: {
+    steps: [
+        {
+          "step": "setSiteOptions",
+          "options": {
+              "blogname": "Blueprint Title",
+              "blogdescription": "A great blog description"
+          }
+        }
+    ],
+  },
+});
+```
+
+For full type-safety when defining your blueprint object, you can import and use the `BlueprintDeclaration` type from the `@wp-playground/blueprints` package:
+
+```TypeScript
+import type { BlueprintDeclaration } from '@wp-playground/blueprints';
+
+const myBlueprint: BlueprintDeclaration = {
+  landingPage: "/wp-admin/",
+  steps: [
+    {
+      "step": "installTheme",
+      "themeData": {
+        "resource": "wordpress.org/themes",
+        "slug": "twentytwentyone"
+      },
+      "options": {
+        "activate": true
+      }
+    }
+  ]
+};
+```
+
+### Mounting a plugin programmatically
+
+It is possible to mount local directories programmatically using `runCLI`. The options `mount` and `mount-before-install` are available. The `hostPath` property expects a path to a directory on your local machine. This path should be relative to where your script is being executed.
+
+```TypeScript
+	cliServer = await runCLI({
+      command: 'server',
+      login: true,
+      'mount-before-install': [
+        {
+          hostPath: './[my-plugin-local-path]',
+          vfsPath: '/wordpress/wp-content/plugins/my-plugin',
+        },
+      ],
+    });
+```
+
+With those options we can combine mounting parts of the project with blueprints, for example:
+
+```TypeScript
+
+import { runCLI, RunCLIArgs, RunCLIServer } from "@wp-playground/cli";
+
+let cliServer: RunCLIServer;
+
+cliServer = await runCLI({
+    command: 'server',
+    php: '8.3',
+    wp: 'latest',
+    login: true,
+    mount: [
+        {
+            "hostPath": "./plugin/",
+            "vfsPath": "/wordpress/wp-content/plugins/playwright-test"
+        }
+    ],
+    blueprint: {
+        steps: [
+            {
+                "step": "activatePlugin",
+                "pluginPath": "/wordpress/wp-content/plugins/playwright-test/plugin-playwright.php"
+            }
+        ]
+    }
+} as RunCLIArgs);
+```