feat: add route control bar and fix replay protocol compliance

Add ROUTE_CONTROL command type and route-control mapping in
AgentCommandController. New RouteControlBar component in the exchange
header shows Start/Stop/Suspend/Resume actions (grouped pill bar) and
a Replay button, gated by agent capabilities and OPERATOR/ADMIN role.

Fix useReplayExchange hook to match protocol section 16: payload now
uses { routeId, exchange: { body, headers }, originalExchangeId, nonce }
instead of the flat { headers, body } format.

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

ui/src/api/queries/commands.ts

@@ -154,22 +154,53 @@ export function useTestExpression() {
   })
 }
 
+// ── Route Control ────────────────────────────────────────────────────────
+
+export function useSendRouteCommand() {
+  return useMutation({
+    mutationFn: async ({ application, action, routeId }: {
+      application: string
+      action: 'start' | 'stop' | 'suspend' | 'resume'
+      routeId: string
+    }) => {
+      const { data, error } = await api.POST('/agents/groups/{group}/commands', {
+        params: { path: { group: application } },
+        body: { type: 'route-control', payload: { routeId, action, nonce: crypto.randomUUID() } } as any,
+      })
+      if (error) throw new Error('Failed to send route command')
+      return data!
+    },
+  })
+}
+
 // ── Replay Exchange ───────────────────────────────────────────────────────
 
 export function useReplayExchange() {
   return useMutation({
     mutationFn: async ({
       agentId,
+      routeId,
       headers,
       body,
+      originalExchangeId,
     }: {
       agentId: string
-      headers: Record<string, string>
+      routeId: string
+      headers?: Record<string, string>
       body: string
+      originalExchangeId?: string
     }) => {
       const { data, error } = await api.POST('/agents/{id}/commands', {
         params: { path: { id: agentId } },
-        body: { type: 'replay', payload: { headers, body } } as any,
+        body: {
+          type: 'replay',
+          payload: {
+            routeId,
+            exchange: { body, headers: headers ?? {} },
+            originalExchangeId,
+            nonce: crypto.randomUUID(),
+          },
+        } as any,
       })
       if (error) throw new Error('Failed to send replay command')
       return data!