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/Psr7/Request.php

@@ -0,0 +1,124 @@
+<?php
+
+declare (strict_types=1);
+namespace DeliciousBrains\WP_Offload_Media\Aws3\GuzzleHttp\Psr7;
+
+use InvalidArgumentException;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\RequestInterface;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\StreamInterface;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\UriInterface;
+/**
+ * PSR-7 request implementation.
+ */
+class Request implements RequestInterface
+{
+    use MessageTrait;
+    /** @var string */
+    private $method;
+    /** @var string|null */
+    private $requestTarget;
+    /** @var UriInterface */
+    private $uri;
+    /**
+     * @param string                               $method  HTTP method
+     * @param string|UriInterface                  $uri     URI
+     * @param (string|string[])[]                  $headers Request headers
+     * @param string|resource|StreamInterface|null $body    Request body
+     * @param string                               $version Protocol version
+     */
+    public function __construct(string $method, $uri, array $headers = [], $body = null, string $version = '1.1')
+    {
+        $this->assertMethod($method);
+        if (!$uri instanceof UriInterface) {
+            $uri = new Uri($uri);
+        }
+        $this->method = \strtoupper($method);
+        $this->uri = $uri;
+        $this->setHeaders($headers);
+        $this->protocol = $version;
+        if (!isset($this->headerNames['host'])) {
+            $this->updateHostFromUri();
+        }
+        if ($body !== '' && $body !== null) {
+            $this->stream = Utils::streamFor($body);
+        }
+    }
+    public function getRequestTarget() : string
+    {
+        if ($this->requestTarget !== null) {
+            return $this->requestTarget;
+        }
+        $target = $this->uri->getPath();
+        if ($target === '') {
+            $target = '/';
+        }
+        if ($this->uri->getQuery() != '') {
+            $target .= '?' . $this->uri->getQuery();
+        }
+        return $target;
+    }
+    public function withRequestTarget($requestTarget) : RequestInterface
+    {
+        if (\preg_match('#\\s#', $requestTarget)) {
+            throw new InvalidArgumentException('Invalid request target provided; cannot contain whitespace');
+        }
+        $new = clone $this;
+        $new->requestTarget = $requestTarget;
+        return $new;
+    }
+    public function getMethod() : string
+    {
+        return $this->method;
+    }
+    public function withMethod($method) : RequestInterface
+    {
+        $this->assertMethod($method);
+        $new = clone $this;
+        $new->method = \strtoupper($method);
+        return $new;
+    }
+    public function getUri() : UriInterface
+    {
+        return $this->uri;
+    }
+    public function withUri(UriInterface $uri, $preserveHost = \false) : RequestInterface
+    {
+        if ($uri === $this->uri) {
+            return $this;
+        }
+        $new = clone $this;
+        $new->uri = $uri;
+        if (!$preserveHost || !isset($this->headerNames['host'])) {
+            $new->updateHostFromUri();
+        }
+        return $new;
+    }
+    private function updateHostFromUri() : void
+    {
+        $host = $this->uri->getHost();
+        if ($host == '') {
+            return;
+        }
+        if (($port = $this->uri->getPort()) !== null) {
+            $host .= ':' . $port;
+        }
+        if (isset($this->headerNames['host'])) {
+            $header = $this->headerNames['host'];
+        } else {
+            $header = 'Host';
+            $this->headerNames['host'] = 'Host';
+        }
+        // Ensure Host is the first header.
+        // See: https://datatracker.ietf.org/doc/html/rfc7230#section-5.4
+        $this->headers = [$header => [$host]] + $this->headers;
+    }
+    /**
+     * @param mixed $method
+     */
+    private function assertMethod($method) : void
+    {
+        if (!\is_string($method) || $method === '') {
+            throw new InvalidArgumentException('Method must be a non-empty string.');
+        }
+    }
+}