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/stackpath.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Providers\Delivery;
+
+class StackPath extends Delivery_Provider {
+
+	/**
+	 * Which storage providers does the delivery provider support, empty means all.
+	 *
+	 * @var array
+	 */
+	protected static $supported_storage_providers = array(
+		// TODO: Add 'do' after testing and documenting.
+		'aws',
+	);
+
+	/**
+	 * @var string
+	 */
+	protected static $provider_name = 'StackPath';
+
+	/**
+	 * @var string
+	 */
+	protected static $provider_short_name = 'StackPath';
+
+	/**
+	 * Used in filters and settings.
+	 *
+	 * @var string
+	 */
+	protected static $provider_key_name = 'stackpath';
+
+	/**
+	 * @var string
+	 */
+	protected static $service_name = 'CDN';
+
+	/**
+	 * @var string
+	 */
+	protected static $service_short_name = 'CDN';
+
+	/**
+	 * Used in filters and settings.
+	 *
+	 * @var string
+	 */
+	protected static $service_key_name = 'cdn';
+
+	/**
+	 * Optional override of "Provider Name" + "Service Name" for friendly name for service.
+	 *
+	 * @var string
+	 */
+	protected static $provider_service_name = 'StackPath';
+
+	/**
+	 * @var string
+	 */
+	protected static $provider_service_quick_start_slug = 'stackpath-setup';
+
+	/**
+	 * @var string
+	 */
+	protected $console_url = 'https://control.stackpath.com/stacks';
+
+	/**
+	 * Title to be shown for provider's console link.
+	 *
+	 * @return string
+	 */
+	public static function get_console_title(): string {
+		return _x( 'Control Portal', 'Provider console link text', 'amazon-s3-and-cloudfront' );
+	}
+}