docs: Update README for v0.4.0

- Update version badge to 0.4.0
- Add CI/CD badge
- Add release package installation instructions
- Add license key section
- Add releases section
- Update from-source instructions for submodules

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -2,10 +2,11 @@
 
 Stream music over ActivityPub - Build your own music streaming platform for Musicians and Labels.
 
-[![Version](https://img.shields.io/badge/version-0.2.0-blue.svg)](CHANGELOG.md)
+[![Version](https://img.shields.io/badge/version-0.4.0-blue.svg)](CHANGELOG.md)
 [![PHP](https://img.shields.io/badge/PHP-%3E%3D8.3-purple.svg)](https://php.net)
 [![WordPress](https://img.shields.io/badge/WordPress-%3E%3D6.4-blue.svg)](https://wordpress.org)
 [![License](https://img.shields.io/badge/license-GPL--2.0%2B-green.svg)](https://www.gnu.org/licenses/gpl-2.0.html)
+[![CI/CD](https://img.shields.io/badge/CI%2FCD-Gitea%20Actions-green.svg)](https://src.bundespruefstelle.ch/magdev/wp-fedistream/actions)
 
 ## Description
 
@@ -31,29 +32,47 @@ WP FediStream is a WordPress plugin that enables musicians, bands, and labels to
 
 - PHP 8.3 or higher
 - WordPress 6.4 or higher
-- Composer (for development/installation)
+- Valid license key (required for frontend features)
 
 ### Optional
 
 - [ActivityPub Plugin](https://wordpress.org/plugins/activitypub/) - For Fediverse integration
 - [WooCommerce](https://woocommerce.com/) 10.0+ - For selling music
 
+## License Key
+
+WP FediStream requires a valid license key for frontend functionality (player, shortcodes, ActivityPub). The admin dashboard works without a license, allowing you to configure the plugin before activation.
+
+To obtain a license key, contact the author or purchase from the official website.
+
 ## Installation
 
-### From Source
+### From Release Package (Recommended)
 
-1. Clone or download the repository to your WordPress plugins directory:
+1. Download the latest release from the [Releases page](https://src.bundespruefstelle.ch/magdev/wp-fedistream/releases)
+
+2. Upload the ZIP file via **Plugins > Add New > Upload Plugin** in WordPress admin
+
+3. Activate the plugin under **Plugins > Installed Plugins**
+
+4. Navigate to **FediStream > Settings** and enter your license key
+
+5. Start using the plugin via the **FediStream** admin menu
+
+### From Source (Development)
+
+1. Clone the repository to your WordPress plugins directory:
 
    ```bash
    cd wp-content/plugins/
-   git clone https://src.bundespruefstelle.ch/magdev/wp-fedistream.git
+   git clone --recurse-submodules https://src.bundespruefstelle.ch/magdev/wp-fedistream.git
    ```
 
 2. Install Composer dependencies:
 
    ```bash
    cd wp-fedistream
-   composer install --no-dev
+   composer install
    ```
 
 3. Activate the plugin in WordPress admin under **Plugins > Installed Plugins**
@@ -133,6 +152,16 @@ wp-fedistream/
 └── wp-fedistream.php  # Plugin entry point
 ```
 
+## Releases
+
+Release packages are automatically built via Gitea Actions when a version tag is pushed. Each release includes:
+
+- Production-ready ZIP package with all dependencies
+- SHA256 checksum for verification
+- Changelog notes extracted from CHANGELOG.md
+
+Download releases from: <https://src.bundespruefstelle.ch/magdev/wp-fedistream/releases>
+
 ## Contributing
 
 This project is in early development. Contributions, bug reports, and feature requests are welcome.