feat: remove licensing system and bump version to 4.0.0-cloudhost

- Remove AS3CF_Pro_Licences_Updates instantiation and all $this->licence
  references from the PHP backend; stub methods return safe defaults
  (is_valid_licence → true, is_licence_over_media_limit → false,
  feature_enabled → true, is_pro_plugin_setup bypasses licence check)
- Remove Licences REST API endpoint from add_api_endpoints()
- Remove 'licence' from allowed settings keys
- Bump version from 3.2.12 to 4.0.0-cloudhost in version.php and plugin header
- Replace licence derived store with hardcoded always-valid writable store
- Simplify enableAssets store to depend only on config.assets_settings
- Remove licence panel row from Nav flyout; remove licence check from
  offload remaining button disabled logic
- Replace Header licence display with "Internal Build" label
- Remove LicencePage route registration from pages.js; drop licence
  import and is_valid guards from all isNextRoute functions
- Rebuild compiled Svelte bundle

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/pro/Header.svelte

@@ -1,26 +1,9 @@
 <script>
-	import {push} from "svelte-spa-router";
-	import {strings, urls} from "../js/stores";
-	import {licence} from "./stores";
 	import Header from "../components/Header.svelte";
-	import Button from "../components/Button.svelte";
 </script>
 
 <Header>
-	{#if $licence.is_set}
-		{#if $licence.is_valid}
-			<div class="licence-type">
-				<img src={$urls.assets + "img/icon/licence-checked.svg"} alt={$strings.licence_checked}/>
-				<a href={$urls.licenses} class="licence" target="_blank">{$licence.plan_plus_licence}</a>
-			</div>
-			<p>{@html $licence.customer}</p>
-		{:else}
-			<div class="licence-type">
-				<img src={$urls.assets + "img/icon/error.svg"} alt={$strings.licence_error}/>
-				<a href={$urls.licenses} class="licence" target="_blank">{$licence.status_description}</a>
-			</div>
-		{/if}
-	{:else}
-		<Button large primary on:click={() => push("/license")}>{$strings.activate_licence}</Button>
-	{/if}
-</Header>
+	<div class="licence-type">
+		<span>Internal Build</span>
+	</div>
+</Header>