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

classes/providers/delivery/other.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Providers\Delivery;
+
+/**
+ * Class Other
+ *
+ * This is a fallback CDN where the user can add their own name.
+ *
+ * @package DeliciousBrains\WP_Offload_Media\Providers\Delivery
+ */
+class Other extends Delivery_Provider {
+
+	/**
+	 * Can the displayed provider service name be overridden by the user?
+	 *
+	 * @var bool
+	 */
+	protected static $provider_service_name_override_allowed = true;
+
+	/**
+	 * @var string
+	 */
+	protected static $provider_name = 'Other';
+
+	/**
+	 * @var string
+	 */
+	protected static $provider_short_name = 'Other';
+
+	/**
+	 * Used in filters and settings.
+	 *
+	 * @var string
+	 */
+	protected static $provider_key_name = 'other';
+
+	/**
+	 * @var string
+	 */
+	protected static $service_name = 'Unknown';
+
+	/**
+	 * @var string
+	 */
+	protected static $service_short_name = 'Unknown';
+
+	/**
+	 * Used in filters and settings.
+	 *
+	 * @var string
+	 */
+	protected static $service_key_name = 'unknown';
+
+	/**
+	 * Optional override of "Provider Name" + "Service Name" for friendly name for service.
+	 *
+	 * @var string
+	 */
+	protected static $provider_service_name = 'Other';
+}