Defer promotion snapshots to campaign activation

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

@@ -191,7 +191,7 @@
     {#if reviewError}<p class="ui-error" role="alert">{reviewError}</p>{/if}
     {#if preview}
         <p><strong>{preview.servers.filter(server => server.tested).length} tested servers</strong> and <strong>{preview.servers.filter(server => !server.tested).length} additional eligible servers</strong>.</p>
-        <p>Confirming queues the file changes. Each server waits until empty and restart capacity is available, then installs its files and restarts. Tested servers only need another activation if their configuration changed or earlier queued work could replace the tested files. Eligibility follows each file's current scope.</p>
+        <p>Confirming creates a campaign and queues the file changes. Each server waits until empty and restart capacity is available, then captures rollback snapshots, installs its files, and restarts. Tested servers keep their pre-beta snapshots and only need another activation if their configuration changed or earlier queued work could replace the tested files. Eligibility follows each file's current scope.</p>
         <p class="muted">Reviewed {$timeFormat.dateTime(preview.createdAt)}. If targets, versions, or composed settings change, you must review again.</p>
         {#each preview.blockers as blocker}<p class="ui-error" role="alert">{blocker}</p>{/each}
         <div class="file-list">{#each preview.files as file}<details open><summary>{file.name} · {artifactVersionLabel(file)} · {file.servers.length} servers</summary><p><code>{file.path}</code> · {file.scope} · SHA {file.sha256.slice(0,12)}</p><ul>{#each file.servers as name}<li><ServerIdentity {name}/><span>{preview.servers.find(server => server.name === name)?.tested ? 'Already tested' : 'Additional target · restart when empty'}</span></li>{/each}</ul></details>{/each}</div>