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/DoctrineCacheAdapter.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\Doctrine\Common\Cache\Cache;
+class DoctrineCacheAdapter implements CacheInterface, Cache
+{
+    /** @var Cache */
+    private $cache;
+    public function __construct(Cache $cache)
+    {
+        $this->cache = $cache;
+    }
+    public function get($key)
+    {
+        return $this->cache->fetch($key);
+    }
+    public function fetch($key)
+    {
+        return $this->get($key);
+    }
+    public function set($key, $value, $ttl = 0)
+    {
+        return $this->cache->save($key, $value, $ttl);
+    }
+    public function save($key, $value, $ttl = 0)
+    {
+        return $this->set($key, $value, $ttl);
+    }
+    public function remove($key)
+    {
+        return $this->cache->delete($key);
+    }
+    public function delete($key)
+    {
+        return $this->remove($key);
+    }
+    public function contains($key)
+    {
+        return $this->cache->contains($key);
+    }
+    public function getStats()
+    {
+        return $this->cache->getStats();
+    }
+}