Restore campaign terminology across UI and docs

src/routes/betas/[id]/+page.svelte

@@ -41,7 +41,7 @@
     const passed = $derived(test?.servers.filter(server => server.passed).length ?? servers.filter(server => server.stage === 'ready').length);
     const ranked = $derived([...servers].sort((a,b) => (a.stage === 'failed' ? 0 : a.stage === 'ready' ? 2 : 1) - (b.stage === 'failed' ? 0 : b.stage === 'ready' ? 2 : 1) || a.server.localeCompare(b.server)));
     const waiting = $derived(ranked.filter(server => server.stage !== 'ready'));
-    const nextAction = $derived(closed ? beta?.state === 'promoted' ? 'Follow the rollout to check activation on additional servers.' : 'Reuse these files and this plan when you are ready to test again.'
+    const nextAction = $derived(closed ? beta?.state === 'promoted' ? 'Follow the campaign to check activation on additional servers.' : 'Reuse these files and this plan when you are ready to test again.'
         : test?.outcome === 'inconclusive' ? 'The deadline passed without enough evidence. Roll back, then reuse this plan with a longer testing window.'
         : test?.outcome === 'paused' ? 'Resume to continue collecting evidence, or start a fresh attempt. The original deadline still applies.'
         : test?.outcome === 'failed' ? 'Investigate the failed check before a fresh attempt, or roll back.'
@@ -137,7 +137,7 @@
         <div class="actions">
             {#if !closed}<Button variant="primary" onclick={reviewPromotion} disabled={beta.state !== 'ready-promote' || acting !== null}>Review promotion</Button><Button variant="danger" onclick={rollback} disabled={acting !== null} loading={acting === 'rollback'}>{beta.state === 'ready-promote' ? 'Reject beta' : 'Roll back'}</Button>{/if}
             {#if closed}<Button href={`/betas/new?reuse=${id}`}>Reuse files and test plan</Button>{/if}
-            {#if promotion}<Button href={`/campaigns/${encodeURIComponent(promotion.id)}`}>View rollout</Button>{/if}
+            {#if promotion}<Button href={`/campaigns/${encodeURIComponent(promotion.id)}`}>View campaign</Button>{/if}
         </div>
         {#if promotion}<p class="muted">{promotion.pending} servers awaiting activation · {promotion.failed} need attention. Promoting a version does not mean it is already running everywhere.</p>{/if}
         {#if flash}<p role="alert" class="ui-error">{flash}</p>{/if}