Always surface a stopped default agent; acknowledge Run now

Activation card: a stopped default agent now always shows the card —
"is it running or just silent?" must never be ambiguous, especially
since automation prompts tag the default agent and go nowhere while
it's stopped. The delayed path still covers running-but-unresponsive.

Run now: the automation prompt is invisible in the timeline, so firing
one now toasts "Asked {agent} to fix the CI failures" / "…address the
review comments". (The prompts already mention the default agent — the
send path tags it on every message — so multi-agent chats route the
work to the default agent by construction.)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

desktop/src/features/chats/ui/ChatDetail.tsx

@@ -539,8 +539,14 @@ export function ChatDetail({
     hasObserver,
     latestOwnMessageNeedsAgent,
   ]);
+  // A stopped default agent always shows the card — "is it running, is it
+  // silent?" must never be ambiguous. The delayed path still covers a
+  // running-but-unresponsive agent.
+  const defaultAgentInactive =
+    defaultAgent != null && !isManagedAgentActive(defaultAgent);
   const shouldShowAgentActivationCard =
-    latestOwnMessageNeedsAgent && (!hasObserver || showDelayedActivationCard);
+    (defaultAgentInactive && latestVisibleMessage != null) ||
+    (latestOwnMessageNeedsAgent && (!hasObserver || showDelayedActivationCard));
   const forceScrollSignature = latestVisibleMessageIsOwn
     ? latestVisibleMessage.id
     : null;
@@ -728,6 +734,7 @@ export function ChatDetail({
           </div>
         </div>
         <ChatWorkPanel
+          agentName={defaultAgent?.name ?? "Fizz"}
           branch={workBranch}
           chatId={chat.id}
           isTurnActive={isChatTurnActive}

desktop/src/features/chats/ui/ChatWorkPanel.tsx

@@ -1,4 +1,5 @@
 import * as React from "react";
+import { toast } from "sonner";
 import {
   ChevronDown,
   CircleCheck,
@@ -51,6 +52,7 @@ const RENUDGE_COOLDOWN_MS = 15 * 60_000;
  * chat's agent automatically (deduped per head sha / open-thread watermark).
  */
 export function ChatWorkPanel({
+  agentName = "Fizz",
   branch = null,
   chatId,
   isTurnActive = false,
@@ -59,6 +61,8 @@ export function ChatWorkPanel({
   prHref,
   projectPath = null,
 }: {
+  /** Default agent's display name — named in the automation feedback. */
+  agentName?: string;
   /** Live branch from the agent's worktree/checkout activity, if any. */
   branch?: string | null;
   chatId: string;
@@ -143,7 +147,9 @@ export function ChatWorkPanel({
     onAutomationPrompt(
       `CI is failing on ${effectiveHref} (${checks.failed} of ${checks.total} checks). Investigate the failures and push fixes until the checks pass.`,
     );
-  }, [chatId, checks, effectiveHref, onAutomationPrompt, pr]);
+    // The prompt itself is invisible in the timeline — acknowledge it.
+    toast.success(`Asked ${agentName} to fix the CI failures`);
+  }, [agentName, chatId, checks, effectiveHref, onAutomationPrompt, pr]);
   const sendCommentNudge = React.useCallback(() => {
     if (!onAutomationPrompt || !effectiveHref) {
       return;
@@ -155,7 +161,8 @@ export function ChatWorkPanel({
     onAutomationPrompt(
       `There are unanswered review comments on ${effectiveHref}. Address each comment and its replies, push any needed changes, reply to the threads, and resolve every conversation that has been addressed.`,
     );
-  }, [chatId, effectiveHref, onAutomationPrompt, openThreads]);
+    toast.success(`Asked ${agentName} to address the review comments`);
+  }, [agentName, chatId, effectiveHref, onAutomationPrompt, openThreads]);
 
   // Automation: prompt the agent on CI failure / newly-open review threads.
   // Watermarks keep this to one nudge per failing sha and per rise in open