feat(ui-flow): audit schedule, digest sync, export-now IPC (Phase 99)

Wire set-audit-export-schedule, run-audit-export-now, and
sync-hook-failure-digest sidecar messages to platform APIs.

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

index.js

@@ -137,6 +137,23 @@ async function dispatchUiMessage (platform, msg, hooks = {}) {
     send({ type: 'hook-failure-digest-export', ...out })
     return true
   }
+  if (t === 'sync-hook-failure-digest') {
+    const digest = await platform.pushHookFailureDigestToMesh()
+    pushState()
+    send({ type: 'hook-failure-digest-synced', digest })
+    return true
+  }
+  if (t === 'set-audit-export-schedule') {
+    await platform.setAuditExportSchedule(msg.schedule || {})
+    pushState()
+    return true
+  }
+  if (t === 'run-audit-export-now') {
+    const out = await platform.runScheduledAuditExportNow()
+    pushState()
+    send({ type: 'audit-export-scheduled', result: out })
+    return true
+  }
   if (t === 'export-integration-worker-script') {
     const script = platform.buildIntegrationWorkerScript(msg.templateId || 'message-logger')
     send({