feat: add processor tracing toggle to exchange detail views

Wire getActions on ProcessorTimeline and RouteFlow to send
SET_TRACED_PROCESSORS commands to all agents of the same application.
Tracing state managed via Zustand store with optimistic UI and rollback.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/api/queries/commands.ts

@@ -0,0 +1,21 @@
+import { useMutation } from '@tanstack/react-query'
+import { api } from '../client'
+
+interface SendGroupCommandParams {
+  group: string
+  type: string
+  payload: Record<string, unknown>
+}
+
+export function useSendGroupCommand() {
+  return useMutation({
+    mutationFn: async ({ group, type, payload }: SendGroupCommandParams) => {
+      const { data, error } = await api.POST('/agents/groups/{group}/commands', {
+        params: { path: { group } },
+        body: { type, payload } as any,
+      })
+      if (error) throw new Error('Failed to send command')
+      return data!
+    },
+  })
+}