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/Api/ErrorParser/RestJsonErrorParser.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\ErrorParser;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Parser\JsonParser;
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Service;
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\StructureShape;
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\CommandInterface;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\ResponseInterface;
+/**
+ * Parses JSON-REST errors.
+ */
+class RestJsonErrorParser extends AbstractErrorParser
+{
+    use JsonParserTrait;
+    private $parser;
+    public function __construct(Service $api = null, JsonParser $parser = null)
+    {
+        parent::__construct($api);
+        $this->parser = $parser ?: new JsonParser();
+    }
+    public function __invoke(ResponseInterface $response, CommandInterface $command = null)
+    {
+        $data = $this->genericHandler($response);
+        // Merge in error data from the JSON body
+        if ($json = $data['parsed']) {
+            $data = \array_replace($data, $json);
+        }
+        // Correct error type from services like Amazon Glacier
+        if (!empty($data['type'])) {
+            $data['type'] = \strtolower($data['type']);
+        }
+        // Retrieve the error code from services like Amazon Elastic Transcoder
+        if ($code = $response->getHeaderLine('x-amzn-errortype')) {
+            $colon = \strpos($code, ':');
+            $data['code'] = $colon ? \substr($code, 0, $colon) : $code;
+        }
+        // Retrieve error message directly
+        $data['message'] = isset($data['parsed']['message']) ? $data['parsed']['message'] : (isset($data['parsed']['Message']) ? $data['parsed']['Message'] : null);
+        $this->populateShape($data, $response, $command);
+        return $data;
+    }
+}