feat: display per-agent model override in agent monitor tree

Parse the model field from Agent/Task tool input and surface it in the
agent monitor panel as a purple subtitle, so users can immediately see
which agents are running on a non-default model.

Closes #207

src/lib/components/AgentMonitorPanel.svelte

@@ -309,6 +309,13 @@
               {agent.description}
             </p>
 
+            <!-- Model override badge -->
+            {#if agent.model}
+              <p class="mt-0.5 text-[10px] text-purple-400 truncate" title="Model: {agent.model}">
+                ✦ {agent.model}
+              </p>
+            {/if}
+
             <!-- Status indicator -->
             <div class="mt-1 flex items-center gap-1">
               {#if agent.status === "running"}

src/lib/stores/agents.test.ts

@@ -43,6 +43,22 @@ describe("agents store", () => {
       expect(agents[0]).toMatchObject(agent);
     });
 
+    it("preserves model field when provided", () => {
+      const agent = createMockAgent({ model: "claude-opus-4-6" });
+      agentStore.addAgent(conversationId, agent);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].model).toBe("claude-opus-4-6");
+    });
+
+    it("leaves model undefined when not provided", () => {
+      const agent = createMockAgent();
+      agentStore.addAgent(conversationId, agent);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].model).toBeUndefined();
+    });
+
     it("assigns a character name and avatar to added agents", () => {
       const agent = createMockAgent();
       agentStore.addAgent(conversationId, agent);

src/lib/tauri.ts

@@ -515,6 +515,7 @@ export async function initializeTauriListeners() {
       agent_id,
       description,
       subagent_type,
+      model,
       started_at,
       conversation_id,
       parent_tool_use_id,
@@ -526,6 +527,7 @@ export async function initializeTauriListeners() {
         agentId: agent_id,
         description,
         subagentType: subagent_type,
+        model,
         startedAt: started_at,
         status: "running",
         parentToolUseId: parent_tool_use_id,

src/lib/types/agents.ts

@@ -6,6 +6,7 @@ export interface AgentInfo {
   agentType?: string;
   description: string;
   subagentType: string;
+  model?: string;
   startedAt: number;
   endedAt?: number;
   status: AgentStatus;
@@ -21,6 +22,7 @@ export interface AgentStartPayload {
   agent_id?: string;
   description: string;
   subagent_type: string;
+  model?: string;
   started_at: number;
   conversation_id?: string;
   parent_tool_use_id?: string;