Tell React Flow which theme it is drawing in

React Flow stamps `colorMode` on its wrapper as a class and defaults it to
`light`. The app's own token scopes are named `.light` / `.dark` — the classes
that let a dashboard be forced to one theme inside a shell on the other — so
every canvas was silently redeclaring the light palette on its own subtree:
white node cards and a white canvas in dark mode, with the inherited
`--foreground` text still near-white and therefore invisible. Home's neurons
had the same fault, drawn with white ring gaps and the light `--primary`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016ZeGnqVsf5VHQqvz4HdUhN

frontend/src/components/Flow/FlowEditor.tsx

@@ -31,6 +31,7 @@ import {
   type MessageSpec,
   type NodeDef_Input,
 } from "@/client"
+import { useTheme } from "@/components/theme-provider"
 import { Button } from "@/components/ui/button"
 import {
   Dialog,
@@ -205,6 +206,7 @@ function FlowEditorInner({
   const { showErrorToast, showSuccessToast } = useCustomToast()
   const { fitView } = useReactFlow()
   const updateNodeInternals = useUpdateNodeInternals()
+  const { resolvedTheme } = useTheme()
 
   const { data: flows } = useSuspenseQuery(flowsQueryOptions())
   const { data: detail } = useSuspenseQuery(flowQueryOptions(flowName))
@@ -1076,6 +1078,10 @@ function FlowEditorInner({
           nodeTypes={nodeTypes}
           edgeTypes={edgeTypes}
           proOptions={{ hideAttribution: true }}
+          // React Flow stamps this on the wrapper as a class, and the app's own
+          // token scopes are named `.light` / `.dark` (index.css) — so leaving it
+          // unset re-themes the whole canvas to light inside a dark shell.
+          colorMode={resolvedTheme}
           fitView
           fitViewOptions={FIT_VIEW}
           // Low enough that the fit can always show the whole graph. A phone is