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/components/DeliverySettingsHeadingRow.svelte

@@ -0,0 +1,72 @@
+<script>
+	import {hasContext, getContext} from "svelte";
+	import {writable} from "svelte/store";
+	import {push} from "svelte-spa-router";
+	import {
+		delivery_provider,
+		settings,
+		storage_provider,
+		strings,
+		urls
+	} from "../js/stores";
+	import PanelRow from "./PanelRow.svelte";
+	import Button from "./Button.svelte";
+
+	// Parent page may want to be locked.
+	let settingsLocked = writable( false );
+
+	if ( hasContext( "settingsLocked" ) ) {
+		settingsLocked = getContext( "settingsLocked" );
+	}
+
+	$: providerType = $settings[ 'delivery-provider' ] === 'storage' ? 'storage' : 'delivery';
+	$: providerKey = providerType === 'storage' ? $storage_provider.provider_key_name : $delivery_provider.provider_key_name;
+</script>
+
+<PanelRow header gradient class="delivery {providerType} {providerKey}">
+	<img src="{$delivery_provider.icon}" alt={$delivery_provider.provider_service_name}/>
+	<div class="provider-details">
+		<h3>{$delivery_provider.provider_service_name}</h3>
+		<p class="console-details">
+			<a href={$urls.delivery_provider_console_url} class="console" target="_blank" title={$strings.view_provider_console}>{$delivery_provider.console_title}</a>
+		</p>
+	</div>
+	<Button outline on:click={() => push('/delivery/provider')} title={$strings.edit_delivery_provider} disabled={$settingsLocked}>{$strings.edit}</Button>
+</PanelRow>
+
+<style>
+	:global(#as3cf-settings.wpome div.panel.settings .header) img {
+		width: var(--as3cf-settings-ctrl-width);
+		height: var(--as3cf-settings-ctrl-width);
+	}
+
+	.provider-details {
+		display: flex;
+		flex-direction: column;
+		flex: auto;
+		margin-left: var(--as3cf-settings-option-indent);
+		z-index: 1;
+	}
+
+	:global(#as3cf-settings.wpome div.panel) .provider-details h3 {
+		margin-left: 0;
+		margin-bottom: 0.5rem;
+	}
+
+	:global(#as3cf-settings.wpome div.panel) .console-details {
+		display: flex;
+		align-items: center;
+		font-size: 0.75rem;
+	}
+
+	.console-details .console {
+		flex: 0 1 min-content;
+		overflow: hidden;
+		white-space: nowrap;
+		text-overflow: ellipsis;
+	}
+
+	:global(#as3cf-settings.wpome div.panel) .console-details a[target="_blank"].console:after {
+		margin-right: 0;
+	}
+</style>