feat: add S3-compatible storage provider (MinIO, Ceph, R2, etc.)

Adds a new 'S3-Compatible Storage' provider that works with any
S3-API-compatible object storage service, including MinIO, Ceph,
Cloudflare R2, Backblaze B2, and others.

Changes:
- New provider class: classes/providers/storage/s3-compatible-provider.php
  - Provider key: s3compatible
  - Reads user-configured endpoint URL from settings
  - Uses path-style URL access (required by most S3-compatible services)
  - Supports credentials via AS3CF_S3COMPAT_ACCESS_KEY_ID /
    AS3CF_S3COMPAT_SECRET_ACCESS_KEY wp-config.php constants
  - Disables AWS-specific features (Block Public Access, Object Ownership)
- New provider SVG icons (s3compatible.svg, -link.svg, -round.svg)
- Registered provider in main plugin class with endpoint setting support
- Updated StorageProviderSubPage to show endpoint URL input for S3-compatible
- Built pro settings bundle with rollup (Svelte 4.2.19)
- Added package.json and updated rollup.config.mjs for pro-only builds

vendor/Aws3/Aws/AwsClientTrait.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Service;
+/**
+ * A trait providing generic functionality for interacting with Amazon Web
+ * Services. This is meant to be used in classes implementing
+ * \Aws\AwsClientInterface
+ */
+trait AwsClientTrait
+{
+    public function getPaginator($name, array $args = [])
+    {
+        $config = $this->getApi()->getPaginatorConfig($name);
+        return new ResultPaginator($this, $name, $args, $config);
+    }
+    public function getIterator($name, array $args = [])
+    {
+        $config = $this->getApi()->getPaginatorConfig($name);
+        if (!$config['result_key']) {
+            throw new \UnexpectedValueException(\sprintf('There are no resources to iterate for the %s operation of %s', $name, $this->getApi()['serviceFullName']));
+        }
+        $key = \is_array($config['result_key']) ? $config['result_key'][0] : $config['result_key'];
+        if ($config['output_token'] && $config['input_token']) {
+            return $this->getPaginator($name, $args)->search($key);
+        }
+        $result = $this->execute($this->getCommand($name, $args))->search($key);
+        return new \ArrayIterator((array) $result);
+    }
+    public function waitUntil($name, array $args = [])
+    {
+        return $this->getWaiter($name, $args)->promise()->wait();
+    }
+    public function getWaiter($name, array $args = [])
+    {
+        $config = isset($args['@waiter']) ? $args['@waiter'] : [];
+        $config += $this->getApi()->getWaiterConfig($name);
+        return new Waiter($this, $name, $args, $config);
+    }
+    public function execute(CommandInterface $command)
+    {
+        return $this->executeAsync($command)->wait();
+    }
+    public function executeAsync(CommandInterface $command)
+    {
+        $handler = $command->getHandlerList()->resolve();
+        return $handler($command);
+    }
+    public function __call($name, array $args)
+    {
+        if (\substr($name, -5) === 'Async') {
+            $name = \substr($name, 0, -5);
+            $isAsync = \true;
+        }
+        if (!empty($this->aliases[\ucfirst($name)])) {
+            $name = $this->aliases[\ucfirst($name)];
+        }
+        $params = isset($args[0]) ? $args[0] : [];
+        if (!empty($isAsync)) {
+            return $this->executeAsync($this->getCommand($name, $params));
+        }
+        return $this->execute($this->getCommand($name, $params));
+    }
+    /**
+     * @param string $name
+     * @param array $args
+     *
+     * @return CommandInterface
+     */
+    public abstract function getCommand($name, array $args = []);
+    /**
+     * @return Service
+     */
+    public abstract function getApi();
+}