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

ui/js/routes.js

@@ -0,0 +1,117 @@
+import {derived, writable, get} from "svelte/store";
+import {wrap} from "svelte-spa-router/wrap";
+
+/**
+ * Creates store of default pages.
+ *
+ * Having a title means inclusion in main tabs.
+ *
+ * @return {Object}
+ */
+function createPages() {
+	// NOTE: get() only resolves after initialization, hence arrow functions for getting titles.
+	const { subscribe, set, update } = writable( [] );
+
+	return {
+		subscribe,
+		set,
+		add( page ) {
+			update( $pages => {
+				return [...$pages, page]
+					.sort( ( a, b ) => {
+						return a.position - b.position;
+					} );
+			} );
+		},
+		withPrefix( prefix = null ) {
+			return get( this ).filter( ( page ) => {
+				return (prefix && page.route.startsWith( prefix )) || !prefix;
+			} );
+		},
+		routes( prefix = null ) {
+			let defaultComponent = null;
+			let defaultUserData = null;
+			const routes = new Map();
+
+			// If a page can be enabled/disabled, check whether it is enabled before displaying.
+			const conditions = [
+				( detail ) => {
+					if (
+						detail.hasOwnProperty( "userData" ) &&
+						detail.userData.hasOwnProperty( "page" ) &&
+						detail.userData.page.hasOwnProperty( "enabled" )
+					) {
+						return detail.userData.page.enabled();
+					}
+
+					return true;
+				}
+			];
+
+			for ( const page of this.withPrefix( prefix ) ) {
+				const userData = { page: page };
+
+				let route = page.route;
+
+				if ( prefix && route !== prefix + "/*" ) {
+					route = route.replace( prefix, "" );
+				}
+
+				routes.set( route, wrap( {
+					component: page.component,
+					userData: userData,
+					conditions: conditions
+				} ) );
+
+				if ( !defaultComponent && page.default ) {
+					defaultComponent = page.component;
+					defaultUserData = userData;
+				}
+			}
+
+			if ( defaultComponent ) {
+				routes.set( "*", wrap( {
+					component: defaultComponent,
+					userData: defaultUserData,
+					conditions: conditions
+				} ) );
+			}
+
+			return routes;
+		},
+		handleRouteEvent( detail ) {
+			if ( detail.hasOwnProperty( "event" ) ) {
+				if ( !detail.hasOwnProperty( "data" ) ) {
+					detail.data = {};
+				}
+
+				// Find the first page that wants to handle the event
+				// , but also let other pages see the event
+				// so they can set any initial state etc.
+				let route = false;
+				for ( const page of get( this ).values() ) {
+					if ( page.events && page.events[ detail.event ] && page.events[ detail.event ]( detail.data ) && !route ) {
+						route = page.route;
+					}
+				}
+
+				if ( route ) {
+					return route;
+				}
+			}
+
+			if ( detail.hasOwnProperty( "default" ) ) {
+				return detail.default;
+			}
+
+			return false;
+		}
+	};
+}
+
+export const pages = createPages();
+
+// Convenience readable store of all routes.
+export const routes = derived( pages, () => {
+	return pages.routes();
+} );