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/SupportPage.svelte

@@ -0,0 +1,76 @@
+<script>
+	import {link} from "svelte-spa-router";
+	import {strings} from "../js/stores";
+	import {licence} from "./stores";
+	import SupportPage from "../components/SupportPage.svelte";
+	import DocumentationSidebar from "./DocumentationSidebar.svelte";
+	import SupportForm from "./SupportForm.svelte";
+	import Notification from "../components/Notification.svelte";
+
+	export let name = "support";
+
+	/**
+	 * Potentially returns an error message detailing a problem with the currently set license key.
+	 *
+	 * @param {Object} licence
+	 *
+	 * @return {string}
+	 */
+	function getLicenceError( licence ) {
+		// If there are any errors, just return the first (there's usually only 1 anyway).
+		if ( licence.hasOwnProperty( "errors" ) && Object.values( licence.errors ).length > 0 ) {
+			return Object.values( licence.errors )[ 0 ];
+		}
+
+		return "";
+	}
+
+	$: licenceError = getLicenceError( $licence );
+</script>
+
+{#if $licence.is_set}
+	{#if $licence.is_valid && licenceError.length === 0}
+		<SupportPage {name} title={$strings.email_support_title} on:routeEvent>
+			<p class="licence-type" slot="header">{@html $licence.your_active_licence}</p>
+			<svelte:fragment slot="content">
+				<SupportForm/>
+			</svelte:fragment>
+
+			<svelte:fragment slot="footer">
+				<DocumentationSidebar/>
+			</svelte:fragment>
+		</SupportPage>
+	{:else}
+		<SupportPage {name} title={$strings.email_support_title} on:routeEvent>
+			<svelte:fragment slot="content">
+				<Notification warning inline>
+					<p>
+						{@html licenceError}
+					</p>
+				</Notification>
+			</svelte:fragment>
+
+			<svelte:fragment slot="footer">
+				<DocumentationSidebar/>
+			</svelte:fragment>
+		</SupportPage>
+	{/if}
+{:else}
+	<SupportPage {name} title={$strings.email_support_title} on:routeEvent>
+		<svelte:fragment slot="content">
+			<Notification warning inline>
+				<p>
+					{$strings.licence_not_entered}
+					<a href="/license" use:link>
+						{$strings.please_enter_licence}
+					</a>
+				</p>
+				<p>{$strings.once_licence_entered}</p>
+			</Notification>
+		</svelte:fragment>
+
+		<svelte:fragment slot="footer">
+			<DocumentationSidebar/>
+		</svelte:fragment>
+	</SupportPage>
+{/if}