Complete workflow navigation and document page groups

src/routes/betas/new/+page.svelte

@@ -1,4 +1,8 @@
 <script lang="ts">
+    import { page } from '$app/stores';
+    import { contextHref, safeReturnHref } from '$lib/navigation-context.js';
+    import BackLink from '$ui/components/BackLink.svelte';
+    import Breadcrumbs from '$ui/components/primitives/Breadcrumbs.svelte';
     import { timeFormat } from '$ui/stores/time-zone.js';
     import { onMount, tick } from 'svelte';
     import { beforeNavigate, goto } from '$app/navigation';
@@ -167,14 +171,16 @@
             const response=await fetch('/api/betas',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({scripts:picks.map(p=>({scriptId:p.scriptId,scriptVersionId:p.versionId})),servers:[...pickedServers],testPlan:parseBetaPlan(testPlan),notes:betaLabel.trim()||undefined,waitForHealth:true,waitForMatch:false})}), body=await response.json();
             if(!response.ok||!body.ok)throw new Error(body.error??'Could not start beta. Review the selected versions and servers.');
             draftReady=false;try{localStorage.removeItem(betaDraftKey);}catch{}allowLeave=true;
-            await goto(`/betas/${body.result.betaId}`);
+            await goto(contextHref(`/betas/${body.result.betaId}`, safeReturnHref($page.url.searchParams.get('returnTo'), '/betas')));
         }catch(error){flash=(error as Error).message;}finally{openingBeta=false;}
     }
 </script>
 
 <svelte:head><title>New beta | Electric Cherry</title></svelte:head>
 <div class="page">
-    <SectionHeader title="New beta" subtitle="Choose exact file versions and test servers, then review before starting.">{#snippet actions()}<Button href="/betas" variant="ghost">Back to betas</Button>{/snippet}</SectionHeader>
+    <Breadcrumbs items={[{ label: 'Betas', href: '/betas' }, { label: 'New beta' }]} />
+    <BackLink fallback="/betas" />
+    <SectionHeader title="New beta" subtitle="Choose exact file versions and test servers, then review before starting." />
     {#if flash}<div class="ui-error" role="alert">{flash}{#if !scripts.length}<Button size="sm" onclick={()=>initialize()}>Retry</Button>{/if}</div>{/if}
     {#if $fleetError}<div class="ui-error" role="alert">{$fleetError}<Button size="sm" onclick={() => refreshFleet(true)}>Retry servers</Button></div>{/if}
     {#if notice}<p role="status" class="notice">{notice}</p>{/if}