fix: correct support email domain and add README

Update support email from flysend.io to flysend.co and add package
documentation with usage examples, configuration, and error handling.

Author: tareq1988

README.md

@@ -0,0 +1,119 @@
+# FlySend PHP SDK
+
+The official PHP SDK for [FlySend](https://flysend.co) — send transactional emails through the FlySend API.
+
+Works with any PHP project. No framework dependencies.
+
+## Requirements
+
+- PHP 8.2+
+- cURL extension
+
+## Installation
+
+```bash
+composer require flysend/flysend-php
+```
+
+## Quick Start
+
+```php
+use FlySend\FlySend;
+
+$flysend = new FlySend('your-api-key');
+
+$response = $flysend->emails->send([
+    'from' => 'hello@example.com',
+    'to' => 'user@example.com',
+    'subject' => 'Welcome!',
+    'html' => '<p>Hello world!</p>',
+]);
+
+echo $response['data']['id']; // email ID
+```
+
+## Configuration
+
+```php
+$flysend = new FlySend(
+    apiKey: 'your-api-key',
+    baseUrl: 'https://api.flysend.co', // optional, for self-hosted instances
+    timeout: 30,                        // optional, default 30s
+);
+```
+
+## Send Email
+
+```php
+$response = $flysend->emails->send([
+    'from'    => 'Company <hello@example.com>',
+    'to'      => 'user@example.com',
+    'subject' => 'Welcome!',
+    'html'    => '<p>Hello!</p>',
+    'text'    => 'Hello!',                              // optional
+    'cc'      => 'cc@example.com',                      // optional
+    'bcc'     => 'bcc@example.com',                     // optional
+    'reply_to' => 'support@example.com',                // optional
+    'tags'    => [                                      // optional
+        ['name' => 'campaign', 'value' => 'welcome'],
+    ],
+    'attachments' => [                                  // optional
+        [
+            'filename'  => 'invoice.pdf',
+            'content'   => base64_encode($pdfContent),
+            'mime_type' => 'application/pdf',
+        ],
+    ],
+]);
+
+echo $response['data']['id']; // email ID
+```
+
+## Batch Send
+
+Send up to 100 emails in a single request:
+
+```php
+$response = $flysend->emails->batch([
+    [
+        'from'    => 'hello@example.com',
+        'to'      => 'user1@example.com',
+        'subject' => 'Hello User 1',
+        'html'    => '<p>Hi!</p>',
+    ],
+    [
+        'from'    => 'hello@example.com',
+        'to'      => 'user2@example.com',
+        'subject' => 'Hello User 2',
+        'html'    => '<p>Hi!</p>',
+    ],
+]);
+
+echo $response['queued_count']; // number of emails queued
+echo $response['error_count'];  // number of failures
+```
+
+## Error Handling
+
+```php
+use FlySend\Exceptions\FlySendException;
+use FlySend\Exceptions\QuotaExceededException;
+use FlySend\Exceptions\ValidationException;
+
+try {
+    $flysend->emails->send([...]);
+} catch (QuotaExceededException $e) {
+    echo 'Quota exceeded. Remaining: ' . $e->quota['remaining'];
+    echo 'Resets at: ' . $e->quota['resets_at'];
+} catch (ValidationException $e) {
+    echo 'Validation errors: ';
+    print_r($e->errors); // ['field' => ['error message', ...]]
+} catch (FlySendException $e) {
+    echo 'API error: ' . $e->getMessage();
+    echo 'Status code: ' . $e->getStatusCode();
+}
+```
+
+## License
+
+MIT

composer.json

@@ -6,7 +6,7 @@
     "authors": [
         {
             "name": "FlySend",
-            "email": "support@flysend.io"
+            "email": "support@flysend.co"
         }
     ],
     "require": {