Retain host and server scope during investigations

src/routes/provisioning/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+    import BackLink from '$ui/components/BackLink.svelte';
     import { timeFormat } from '$ui/stores/time-zone.js';
     import { onMount } from 'svelte';
     import { page } from '$app/stores';
@@ -112,6 +113,7 @@
     <SectionHeader title="Provisioning" subtitle="Create, start, restart, rebuild, stop, and destroy server instances.">
         {#snippet actions()}<Button onclick={() => lifecycleOpen = true}>Manage server</Button><Button variant="primary" onclick={() => open = true}>Create server</Button><details class="fleet-actions"><summary>Fleet actions</summary><Button variant="danger" onclick={() => housePartyOpen = true}>Destroy fleet…</Button></details>{/snippet}
     </SectionHeader>
+    {#if $page.url.searchParams.has('returnTo')}<BackLink fallback="/" />{/if}
     <Tabs {tabs} bind:value={tab} onchange={() => saveContext(true)} ariaLabel="Provisioning views" idPrefix="deployment-tabs" panelId="deployment-panel" />
     <LifecycleDialog bind:open={lifecycleOpen} />
     <DeployServerDialog bind:open />