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/GuzzleHttp/Exception/BadResponseException.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\GuzzleHttp\Exception;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\RequestInterface;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\ResponseInterface;
+/**
+ * Exception when an HTTP error occurs (4xx or 5xx error)
+ */
+class BadResponseException extends RequestException
+{
+    public function __construct(string $message, RequestInterface $request, ResponseInterface $response, ?\Throwable $previous = null, array $handlerContext = [])
+    {
+        parent::__construct($message, $request, $response, $previous, $handlerContext);
+    }
+    /**
+     * Current exception and the ones that extend it will always have a response.
+     */
+    public function hasResponse() : bool
+    {
+        return \true;
+    }
+    /**
+     * This function narrows the return type from the parent class and does not allow it to be nullable.
+     */
+    public function getResponse() : ResponseInterface
+    {
+        /** @var ResponseInterface */
+        return parent::getResponse();
+    }
+}