Let a node's failure outlive the run that followed it

A node's error cleared the moment it ran again, so a failure that genuinely
fired an alert could leave no trace on the canvas by the time anyone looked.
The engine records it now — on the node's status, so it survives a reload and
every client agrees — and reading the traceback is what clears it. The seam is
the event bus, which is where every failing path already meets: a queued live
run, an explicit run, a preview, and a single triggered node all publish
`node_error`, while the controller's own observer would have seen only one of
them.

That was half the confusion. The other half: clicking a failed neuron on Home
often landed on a flow where everything looked fine. Nodes merge into one
neuron by instance key — every InfluxDB node pointing at the same bucket is one
neuron — and the click went to whichever flow contributed a member first, not
the one that failed. It now goes to the failing member and selects it, and the
canvas marks a failing node rather than leaving it to the dot alone.

The inject node emitted one payload to every port it declared, whatever their
types, so an inject on a bool port carrying the text "true" raised at publish
time. Each port gets its own field now, typed and parsed by that port's dtype,
and remembers what it last sent. A port that is renamed carries its value with
it; one that is removed takes its value with it. An inject written before this
keeps emitting exactly what it did.

The derived-cron chip also appeared on the delay node, where `interval` is a
rate limit and a schedule derived from it means nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uq8mtNb97A7praJLyeEYgs

frontend/src/components/Flow/useFlowSocket.ts

@@ -3,6 +3,7 @@ import { useQueryClient } from "@tanstack/react-query"
 import { useEffect } from "react"
 
 import { OpenAPI } from "@/client"
+import { dashboardKeys, panelKeys } from "@/components/Dashboard/queries"
 import { connectionStore } from "@/lib/connectionStore"
 import { apiToken } from "@/lib/portal"
 import { type LogLine, liveStore, type ValueSource } from "./liveStore"
@@ -87,6 +88,7 @@ type FlowEvent =
       nodes: { id: string; status: string; error?: string | null }[]
       paused?: string[]
     }
+  | { type: "dashboard_changed"; dashboard?: string; ts?: number }
 
 function socketUrl(): string {
   const base = String(OpenAPI.BASE || window.location.origin)
@@ -237,6 +239,18 @@ function connect() {
         // markers on the flow chips are stale until the list is refetched.
         client?.invalidateQueries({ queryKey: flowKeys.all })
         break
+      case "dashboard_changed":
+        // Someone published, or changed which dashboards a panel shows. Refetch
+        // rather than reload: a wall screen must not blank or sign in again.
+        // `exact` matters — the list key is a prefix of every detail key,
+        // including the draft an editor may have open.
+        client?.invalidateQueries({ queryKey: dashboardKeys.all, exact: true })
+        client?.invalidateQueries({
+          queryKey: message.dashboard
+            ? dashboardKeys.detail(message.dashboard)
+            : panelKeys.all,
+        })
+        break
     }
   }