Keep the engine's own history, and a screen that reads it

A second bus subscriber folds executions, errors, timings and queue lag
into per-minute rollups, keeps failures with their traceback and an audit
trail of who published what, and records one row per cascade — manual runs
and previews included, under an id of their own that writes no idempotency
markers. Read back through /observability/*, which always answers 200 so a
degraded engine still renders its own health screen.

Also fixes two things found on the way: node-health alerts read `status`
where the engine publishes `health`, so a device dropping never alerted
anyone, and the Redis queue reported `parked: 0` whatever was held.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017MeiWk3Yq12n2pTvnQWYvt

frontend/src/routeTree.gen.ts

@@ -21,6 +21,7 @@ import { Route as OauthAuthorizeRouteImport } from './routes/oauth.authorize'
 import { Route as LayoutSettingsRouteImport } from './routes/_layout/settings'
 import { Route as LayoutSecretsRouteImport } from './routes/_layout/secrets'
 import { Route as LayoutModulesRouteImport } from './routes/_layout/modules'
+import { Route as LayoutHealthRouteImport } from './routes/_layout/health'
 import { Route as LayoutAlertsRouteImport } from './routes/_layout/alerts'
 import { Route as LayoutAdminRouteImport } from './routes/_layout/admin'
 import { Route as LayoutFlowsIndexRouteImport } from './routes/_layout/flows/index'
@@ -86,6 +87,11 @@ const LayoutModulesRoute = LayoutModulesRouteImport.update({
   path: '/modules',
   getParentRoute: () => LayoutRoute,
 } as any)
+const LayoutHealthRoute = LayoutHealthRouteImport.update({
+  id: '/health',
+  path: '/health',
+  getParentRoute: () => LayoutRoute,
+} as any)
 const LayoutAlertsRoute = LayoutAlertsRouteImport.update({
   id: '/alerts',
   path: '/alerts',
@@ -125,6 +131,7 @@ export interface FileRoutesByFullPath {
   '/signup': typeof SignupRoute
   '/admin': typeof LayoutAdminRoute
   '/alerts': typeof LayoutAlertsRoute
+  '/health': typeof LayoutHealthRoute
   '/modules': typeof LayoutModulesRoute
   '/secrets': typeof LayoutSecretsRoute
   '/settings': typeof LayoutSettingsRoute
@@ -143,6 +150,7 @@ export interface FileRoutesByTo {
   '/signup': typeof SignupRoute
   '/admin': typeof LayoutAdminRoute
   '/alerts': typeof LayoutAlertsRoute
+  '/health': typeof LayoutHealthRoute
   '/modules': typeof LayoutModulesRoute
   '/secrets': typeof LayoutSecretsRoute
   '/settings': typeof LayoutSettingsRoute
@@ -163,6 +171,7 @@ export interface FileRoutesById {
   '/signup': typeof SignupRoute
   '/_layout/admin': typeof LayoutAdminRoute
   '/_layout/alerts': typeof LayoutAlertsRoute
+  '/_layout/health': typeof LayoutHealthRoute
   '/_layout/modules': typeof LayoutModulesRoute
   '/_layout/secrets': typeof LayoutSecretsRoute
   '/_layout/settings': typeof LayoutSettingsRoute
@@ -184,6 +193,7 @@ export interface FileRouteTypes {
     | '/signup'
     | '/admin'
     | '/alerts'
+    | '/health'
     | '/modules'
     | '/secrets'
     | '/settings'
@@ -202,6 +212,7 @@ export interface FileRouteTypes {
     | '/signup'
     | '/admin'
     | '/alerts'
+    | '/health'
     | '/modules'
     | '/secrets'
     | '/settings'
@@ -221,6 +232,7 @@ export interface FileRouteTypes {
     | '/signup'
     | '/_layout/admin'
     | '/_layout/alerts'
+    | '/_layout/health'
     | '/_layout/modules'
     | '/_layout/secrets'
     | '/_layout/settings'
@@ -330,6 +342,13 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof LayoutModulesRouteImport
       parentRoute: typeof LayoutRoute
     }
+    '/_layout/health': {
+      id: '/_layout/health'
+      path: '/health'
+      fullPath: '/health'
+      preLoaderRoute: typeof LayoutHealthRouteImport
+      parentRoute: typeof LayoutRoute
+    }
     '/_layout/alerts': {
       id: '/_layout/alerts'
       path: '/alerts'
@@ -391,6 +410,7 @@ const CanvasRouteWithChildren =
 interface LayoutRouteChildren {
   LayoutAdminRoute: typeof LayoutAdminRoute
   LayoutAlertsRoute: typeof LayoutAlertsRoute
+  LayoutHealthRoute: typeof LayoutHealthRoute
   LayoutModulesRoute: typeof LayoutModulesRoute
   LayoutSecretsRoute: typeof LayoutSecretsRoute
   LayoutSettingsRoute: typeof LayoutSettingsRoute
@@ -402,6 +422,7 @@ interface LayoutRouteChildren {
 const LayoutRouteChildren: LayoutRouteChildren = {
   LayoutAdminRoute: LayoutAdminRoute,
   LayoutAlertsRoute: LayoutAlertsRoute,
+  LayoutHealthRoute: LayoutHealthRoute,
   LayoutModulesRoute: LayoutModulesRoute,
   LayoutSecretsRoute: LayoutSecretsRoute,
   LayoutSettingsRoute: LayoutSettingsRoute,