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/pro/ToolsPage.svelte

@@ -0,0 +1,29 @@
+<script>
+	import {setContext} from "svelte";
+	import {strings} from "../js/stores";
+	import {tools, toolsLocked} from "./stores";
+	import Page from "../components/Page.svelte";
+	import Notifications from "../components/Notifications.svelte";
+	import ToolNotification from "./ToolNotification.svelte";
+	import ToolPanel from "./ToolPanel.svelte";
+	import NoTools from "./NoTools.svelte";
+
+	export let name = "tools";
+
+	// Let all child components know if tools are currently locked.
+	// All panels etc respond to settingsLocked, so we fake it here as we're not in a settings context.
+	setContext( "settingsLocked", toolsLocked );
+</script>
+
+<Page {name} on:routeEvent>
+	<Notifications tab={name} component={ToolNotification}/>
+	<h2 class="page-title">{$strings.tools_title}</h2>
+
+	<div class="tools-page wrapper">
+		{#each Object.values( $tools ).filter( ( tool ) => tool.render ) as tool (tool.id)}
+			<ToolPanel {tool}/>
+		{:else}
+			<NoTools/>
+		{/each}
+	</div>
+</Page>