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/Parser/NonSeekableStreamDecodingEventStreamIterator.php

@@ -0,0 +1,81 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Parser;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\GuzzleHttp\Psr7;
+use DeliciousBrains\WP_Offload_Media\Aws3\Psr\Http\Message\StreamInterface;
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Parser\Exception\ParserException;
+/**
+ * @inheritDoc
+ */
+class NonSeekableStreamDecodingEventStreamIterator extends DecodingEventStreamIterator
+{
+    /** @var array $tempBuffer */
+    private $tempBuffer;
+    /**
+     * NonSeekableStreamDecodingEventStreamIterator constructor.
+     *
+     * @param StreamInterface $stream
+     */
+    public function __construct(StreamInterface $stream)
+    {
+        $this->stream = $stream;
+        if ($this->stream->isSeekable()) {
+            throw new \InvalidArgumentException('The stream provided must be not seekable.');
+        }
+        $this->tempBuffer = [];
+    }
+    /**
+     * @inheritDoc
+     *
+     * @return array
+     */
+    protected function parseEvent() : array
+    {
+        $event = [];
+        $this->hashContext = \hash_init('crc32b');
+        $prelude = $this->parsePrelude()[0];
+        list($event[self::HEADERS], $numBytes) = $this->parseHeaders($prelude[self::LENGTH_HEADERS]);
+        $event[self::PAYLOAD] = Psr7\Utils::streamFor($this->readAndHashBytes($prelude[self::LENGTH_TOTAL] - self::BYTES_PRELUDE - $numBytes - self::BYTES_TRAILING));
+        $calculatedCrc = \hash_final($this->hashContext, \true);
+        $messageCrc = $this->stream->read(4);
+        if ($calculatedCrc !== $messageCrc) {
+            throw new ParserException('Message checksum mismatch.');
+        }
+        return $event;
+    }
+    protected function readAndHashBytes($num) : string
+    {
+        $bytes = '';
+        while (!empty($this->tempBuffer) && $num > 0) {
+            $byte = \array_shift($this->tempBuffer);
+            $bytes .= $byte;
+            $num = $num - 1;
+        }
+        $bytes = $bytes . $this->stream->read($num);
+        \hash_update($this->hashContext, $bytes);
+        return $bytes;
+    }
+    // Iterator Functionality
+    #[\ReturnTypeWillChange]
+    public function rewind()
+    {
+        $this->currentEvent = $this->parseEvent();
+    }
+    public function next()
+    {
+        $this->tempBuffer[] = $this->stream->read(1);
+        if ($this->valid()) {
+            $this->key++;
+            $this->currentEvent = $this->parseEvent();
+        }
+    }
+    /**
+     * @return bool
+     */
+    #[\ReturnTypeWillChange]
+    public function valid()
+    {
+        return !$this->stream->eof();
+    }
+}