Preserve originating views through detail navigation

src/routes/collections/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+    import { contextHref } from '$lib/navigation-context.js';
     import { onMount } from 'svelte';
     import { page } from '$app/stores';
     import { goto } from '$app/navigation';
@@ -134,7 +135,7 @@
         {#if launchesLoading}<p>Loading collection launches…</p>
         {:else if visibleLaunches.length}
             <div class="launches">{#each visibleLaunches.slice(0,launchLimit) as collection (collection.id)}
-                <a class="collection-row" href="/collections/launches/{collection.id}">
+                <a class="collection-row" href={contextHref(`/collections/launches/${collection.id}`, $page.url)}>
                     <div class="row-head"><strong>{collection.name}</strong><Badge variant={collection.active ? 'info' : collection.failed ? 'danger' : 'online'}>{collection.active ? collection.provisioning + collection.verifying ? collection.mode === 'exact' ? 'Applying collection' : 'Launching' : 'Queued' : collection.failed ? 'Needs attention' : 'Completed'}</Badge></div>
                     <div class="collection-counts"><span><strong>{collection.done} / {collection.total}</strong> {collection.mode === 'exact' ? 'completed' : 'ready'}</span>{#if collection.provisioning + collection.verifying}<span>{collection.provisioning + collection.verifying} {collection.mode === 'exact' ? 'in progress' : 'launching'}</span>{/if}{#if collection.queued}<span>{collection.queued} queued</span>{/if}{#if collection.failed}<span class="error">{collection.failed} need attention</span>{/if}</div>
                     <div class="collection-meter" aria-hidden="true"><span class="verified" style:width={`${collection.done / (collection.total || 1) * 100}%`}></span><span class="unsuccessful" style:width={`${collection.failed / (collection.total || 1) * 100}%`}></span></div>

src/routes/collections/launches/[id]/+page.svelte

@@ -1,4 +1,6 @@
 <script lang="ts">
+    import { contextHref } from '$lib/navigation-context.js';
+    import BackLink from '$ui/components/BackLink.svelte';
     import { onMount } from 'svelte';
     import { pollVisible } from '$ui/poll.js';
     import ServerIdentity from '$ui/components/ServerIdentity.svelte';
@@ -54,6 +56,7 @@
     <SectionHeader title={collection?.name ?? 'Collection launch'}>
         {#snippet crumbs()}<Breadcrumbs items={[{ label: 'Collections', href: '/collections' }, { label: 'Collection launch' }]} />{/snippet}
     </SectionHeader>
+    <BackLink fallback="/collections?view=active" />
     {#if error}<p class="error" role="alert">{error} <button onclick={load}>Retry</button></p>{/if}
     {#if collection && detail}
         <section class="summary" aria-label="Collection progress">
@@ -78,7 +81,7 @@
             <section class="current-launches" aria-label="In progress">
                 <span class="eyebrow">In progress</span>
                 {#each currentServers as server (server.id)}
-                    <a class="current-launch" href="/provisioning/{server.id}">
+                    <a class="current-launch" href={contextHref(`/provisioning/${server.id}`, $page.url)}>
                         <span class="activity" aria-hidden="true"></span>
                         <div><strong>{server.action === 'destroy' ? 'Removing: ' : ''}<HistoricalServerIdentity name={server.server} deletedAt={server.server_deleted_at} /></strong><p>{server.state === 'awaiting-health' ? 'Checking the container, connection, and expected map.' : server.stage}</p></div>
                         <span class="operation-link">Follow progress <span aria-hidden="true">→</span></span>
@@ -92,7 +95,7 @@
                     <p>{queueHint(firstQueued)} Provisioning starts each server when its host and capacity are ready. Progress updates automatically.</p>
                     {#if otherLaunches.length}
                         <p>Other servers currently launching:</p>
-                        <div class="other-launches">{#each otherLaunches as active (active.id)}<a href="/provisioning/{active.id}"><ServerIdentity name={active.server} /> <span aria-hidden="true">→</span></a>{/each}</div>
+                        <div class="other-launches">{#each otherLaunches as active (active.id)}<a href={contextHref(`/provisioning/${active.id}`, $page.url)}><ServerIdentity name={active.server} /> <span aria-hidden="true">→</span></a>{/each}</div>
                     {/if}
                 </div>
             </aside>
@@ -108,7 +111,7 @@
             <ol class="servers">
                 {#each detail.servers as server, index (server.id)}
                     <li class:launching={launching(server)} class:attention={needsAttention(server)}>
-                        <a class="server" href="/provisioning/{server.id}">
+                        <a class="server" href={contextHref(`/provisioning/${server.id}`, $page.url)}>
                             <span class="order" class:ready={server.state === 'done'} aria-hidden="true">{server.state === 'done' ? '✓' : String(index + 1).padStart(2, '0')}</span>
                             <div class="server-content">
                                 <div class="server-heading"><strong><HistoricalServerIdentity name={server.server} deletedAt={server.server_deleted_at} /></strong><Badge variant={needsAttention(server) ? 'danger' : server.state === 'done' ? 'online' : launching(server) ? 'info' : 'neutral'}>{stateLabel(server)}</Badge></div>