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

assets/js/modal.js

@@ -0,0 +1,161 @@
+var as3cfModal = (function( $ ) {
+
+	var modal = {
+		prefix: 'as3cf',
+		loading: false,
+		dismissible: true
+	};
+
+	var modals = {};
+
+	/**
+	 * Target to key
+	 *
+	 * @param {string} target
+	 *
+	 * @return {string}
+	 */
+	function targetToKey( target ) {
+		return target.replace( /[^a-z]/g, '' );
+	}
+
+	/**
+	 * Check if modal exists in DOM or in Memory.
+	 *
+	 * @param {string} target
+	 *
+	 * @return {boolean}
+	 */
+	modal.exists = function( target ) {
+		var key = targetToKey( target );
+
+		if ( undefined !== modals[ key ] ) {
+			return true;
+		}
+
+		if ( $( target ).length ) {
+			return true;
+		}
+
+		return false;
+	};
+
+	/**
+	 * Open modal
+	 *
+	 * @param {string}   target
+	 * @param {function} callback
+	 * @param {string}   customClass
+	 */
+	modal.open = function( target, callback, customClass ) {
+		var key = targetToKey( target );
+
+		// Overlay
+		$( 'body' ).append( '<div id="as3cf-overlay"></div>' );
+		var $overlay = $( '#as3cf-overlay' );
+
+		// Modal container
+		if ( modal.dismissible ) {
+			$overlay.append( '<div id="as3cf-modal"><span class="close-as3cf-modal">×</span></div>' );
+		} else {
+			$overlay.append( '<div id="as3cf-modal"></div>' );
+		}
+
+		var $modal = $( '#as3cf-modal' );
+
+		if ( undefined === modals[ key ] ) {
+			var content = $( target );
+			modals[ key ] = content.clone( true ).css( 'display', 'block' );
+			content.remove();
+		}
+		$modal.data( 'as3cf-modal-target', target ).append( modals[ key ] );
+
+		if ( undefined !== customClass ) {
+			$modal.addClass( customClass );
+		}
+
+		if ( 'function' === typeof callback ) {
+			callback( target );
+		}
+
+		// Handle modals taller than window height,
+		// overflow & padding-right remove duplicate scrollbars.
+		$( 'body' ).addClass( 'as3cf-modal-open' );
+
+		$overlay.fadeIn( 150 );
+		$modal.fadeIn( 150 );
+
+		$( 'body' ).trigger( 'as3cf-modal-open', [ target ] );
+	};
+
+	/**
+	 * Close modal
+	 *
+	 * @param {function} callback
+	 */
+	modal.close = function( callback ) {
+		if ( modal.loading || ! modal.dismissible ) {
+			return;
+		}
+
+		var target = $( '#as3cf-modal' ).data( 'as3cf-modal-target' );
+
+		$( '#as3cf-overlay' ).fadeOut( 150, function() {
+			$( 'body' ).removeClass( 'as3cf-modal-open' );
+
+			$( this ).remove();
+
+			if ( 'function' === typeof callback ) {
+				callback( target );
+			}
+		} );
+
+		$( 'body' ).trigger( 'as3cf-modal-close', [ target ] );
+	};
+
+	/**
+	 * Set loading state
+	 *
+	 * @param {boolean} state
+	 */
+	modal.setLoadingState = function( state ) {
+		modal.loading = state;
+	};
+
+	/**
+	 * Set dismissible state.
+	 *
+	 * @param {boolean} state
+	 */
+	modal.setDismissibleState = function( state ) {
+		modal.dismissible = state;
+	};
+
+	// Setup click handlers
+	$( document ).ready( function() {
+
+		$( 'body' ).on( 'click', '[data-as3cf-modal]', function( e ) {
+			e.preventDefault();
+			modal.open( $( this ).data( 'as3cf-modal' ) + '.' + modal.prefix );
+		} );
+
+		$( 'body' ).on( 'click', '#as3cf-overlay, .close-as3cf-modal', function( e ) {
+			if ( 'A' === e.target.tagName ) {
+				return;
+			}
+
+			e.preventDefault();
+
+			// Don't allow children to bubble up click event
+			if ( e.target !== this ) {
+				return false;
+			}
+
+			modal.close();
+		} );
+
+	} );
+
+	return modal;
+
+})( jQuery );