feat(ui-flow): digest relay handoff IPC and semver announce option

Handle get-digest-relay-handoff and pass allowDowngrade to announceWorkerRelease.

Co-authored-by: Cursor <[email protected]>

index.js

@@ -110,11 +110,17 @@ async function dispatchUiMessage (platform, msg, hooks = {}) {
     pushState()
     return true
   }
+  if (t === 'get-digest-relay-handoff') {
+    const handoff = await platform.getLastDigestRelayHandoff()
+    send({ type: 'digest-relay-handoff', handoff })
+    return true
+  }
   if (t === 'announce-worker-release') {
     await platform.announceWorkerRelease({
       workerVersion: msg.workerVersion,
       pearUri: msg.pearUri,
-      releaseNotes: msg.releaseNotes
+      releaseNotes: msg.releaseNotes,
+      allowDowngrade: !!msg.allowDowngrade
     })
     pushState()
     return true