Preserve originating views through detail navigation

src/routes/campaigns/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+    import { contextHref } from '$lib/navigation-context.js';
     import { timeFormat } from '$ui/stores/time-zone.js';
     import { onMount } from 'svelte';
     import { page } from '$app/stores';
@@ -217,7 +218,7 @@
         {#if flash && flashId === d.id}<div class="result" class:result-error={flashError} role={flashError ? 'alert' : 'status'}>{flash}</div>{/if}
         <div class="row-head">
             <div class="row-head-l">
-                <a class="action" href="/campaigns/{d.id}">{d.action} campaign <span class="sr-only">{d.id}</span></a>
+                <a class="action" href={contextHref(`/campaigns/${d.id}`, $page.url)}>{d.action} campaign <span class="sr-only">{d.id}</span></a>
                 {#if d.action === 'promote' || d.action === 'rollback'}
                     <span class="target">{scriptSummary(d)}</span>
                 {/if}

src/routes/campaigns/[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 { timeFormat } from '$ui/stores/time-zone.js';
     import { onMount } from 'svelte';
     import { pollVisible } from '$ui/poll.js';
@@ -136,6 +138,7 @@
                 ]} />
             {/snippet}
         </SectionHeader>
+    <BackLink fallback="/campaigns" />
 
         <section class="outcome" aria-label="Campaign outcome">
             <h2>{completed} / {detail.servers.length} servers activated{unresolved ? ` · ${unresolved} unresolved` : ''}{withdrawn ? ` · ${withdrawn} withdrawn` : ''}{deletedIncomplete ? ` · ${deletedIncomplete} deleted before activation` : ''}</h2>
@@ -145,7 +148,7 @@
             {:else}<p>Every recorded server completed activation.</p>{/if}
         </section>
 
-        {#if detail.watchdogIncidentId}<p class="watchdog-source">Started by Maintenance · <a href={`/maintenance/${encodeURIComponent(detail.watchdogIncidentId)}`}>View incident and recovery history</a></p>{/if}
+        {#if detail.watchdogIncidentId}<p class="watchdog-source">Started by Maintenance · <a href={contextHref(`/maintenance/${encodeURIComponent(detail.watchdogIncidentId)}`, $page.url)}>View incident and recovery history</a></p>{/if}
 
         {#if detail.servers.some(server => !server.server_deleted_at && ['held', 'manual'].includes(server.restart_state))}
             <div><Button onclick={resume} loading={resuming} disabled={resuming}>Resume when empty</Button><p>Apply held changes and restart after the safety checks pass.</p></div>
@@ -170,7 +173,7 @@
                 {#each rankedServers as s (s.server)}
                     <div class="srv-row">
                         <div class="srv-l">
-                            <span class="srv-name"><HistoricalServerIdentity name={s.server} deletedAt={s.server_deleted_at} href={`/servers/${encodeURIComponent(s.server)}`} /></span>
+                            <span class="srv-name"><HistoricalServerIdentity name={s.server} deletedAt={s.server_deleted_at} href={contextHref(`/servers/${encodeURIComponent(s.server)}`, $page.url)} /></span>
                             {#if s.error}
                                 <span class="err">{s.error}</span>
                             {/if}