Add timestamp behavior E2E tests and verify bug is fixed

WHAT:
- Added initializeAgent() and clearAgentAttention() methods to DaemonClient
  (packages/server/src/server/test-utils/daemon-client.ts:268-304)
- Added E2E tests for timestamp behavior
  (packages/server/src/server/daemon.e2e.test.ts:482-570):
  - "opening agent without interaction does not update timestamp"
  - "sending message DOES update timestamp"

RESULT:
Bug verified as already fixed in commit 32e111e (Dec 2, 2025) which removed
timestamp thrashing - previously lastActivityAt/updatedAt was updated on
every agent_stream event (15+ times/second during streaming).

Server only sets agent.updatedAt in:
- recordUserMessage (agent-manager.ts:436)
- handleStreamEvent (agent-manager.ts:864)
NOT in clearAgentAttention or initializeAgent flows.

EVIDENCE:
- npm run test --workspace=@paseo/server -- daemon.e2e.test.ts -t "timestamp"
  (2 passed in 9.08s)
- Playwright test showed agent stayed in position 4 with unchanged timestamp
  after clicking

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/server/src/server/daemon.e2e.test.ts

@@ -479,6 +479,97 @@ describe("daemon E2E", () => {
     );
   });
 
+  describe("timestamp behavior", () => {
+    test(
+      "opening agent without interaction does not update timestamp",
+      async () => {
+        const cwd = tmpCwd();
+
+        // Create a Codex agent
+        const agent = await ctx.client.createAgent({
+          provider: "codex",
+          cwd,
+          title: "Timestamp Test Agent",
+        });
+
+        expect(agent.id).toBeTruthy();
+        expect(agent.status).toBe("idle");
+
+        // Record the initial updatedAt timestamp
+        const initialUpdatedAt = agent.updatedAt;
+        expect(initialUpdatedAt).toBeTruthy();
+
+        // Wait a bit to ensure any timestamp update would be visible
+        await new Promise((resolve) => setTimeout(resolve, 1500));
+
+        // Clear message queue before the "click" action
+        ctx.client.clearMessageQueue();
+
+        // Simulate clicking on the agent (initialize_agent_request)
+        // This is what happens when the user opens an agent in the UI
+        const refreshedState = await ctx.client.initializeAgent(agent.id);
+
+        // Verify agent is still idle
+        expect(refreshedState.status).toBe("idle");
+
+        // CRITICAL: The timestamp should NOT have changed
+        // Just opening/clicking an agent should not update its updatedAt
+        expect(refreshedState.updatedAt).toBe(initialUpdatedAt);
+
+        // Also clear attention (what happens when opening an agent with notification)
+        await ctx.client.clearAgentAttention(agent.id);
+
+        // Get the state again after clearing attention
+        const stateAfterClear = await ctx.client.initializeAgent(agent.id);
+
+        // Timestamp should STILL not have changed
+        expect(stateAfterClear.updatedAt).toBe(initialUpdatedAt);
+
+        // Cleanup
+        rmSync(cwd, { recursive: true, force: true });
+      },
+      60000
+    );
+
+    test(
+      "sending message DOES update timestamp",
+      async () => {
+        const cwd = tmpCwd();
+
+        // Create a Codex agent
+        const agent = await ctx.client.createAgent({
+          provider: "codex",
+          cwd,
+          title: "Timestamp Update Test Agent",
+        });
+
+        expect(agent.id).toBeTruthy();
+        expect(agent.status).toBe("idle");
+
+        // Record the initial updatedAt timestamp
+        const initialUpdatedAt = new Date(agent.updatedAt);
+
+        // Wait a bit to ensure timestamp difference is visible
+        await new Promise((resolve) => setTimeout(resolve, 1500));
+
+        // Send a message (this SHOULD update the timestamp)
+        await ctx.client.sendMessage(agent.id, "Say 'test' and nothing else");
+
+        // Wait for agent to complete
+        const finalState = await ctx.client.waitForAgentIdle(agent.id, 120000);
+        expect(finalState.status).toBe("idle");
+
+        // The timestamp SHOULD have been updated (should be later than initial)
+        const finalUpdatedAt = new Date(finalState.updatedAt);
+        expect(finalUpdatedAt.getTime()).toBeGreaterThan(initialUpdatedAt.getTime());
+
+        // Cleanup
+        rmSync(cwd, { recursive: true, force: true });
+      },
+      180000
+    );
+  });
+
   // Claude permission tests are skipped due to SDK behavior:
   // - The sandbox config IS passed correctly to Claude SDK
   // - Claude executes tool calls without requesting permission

packages/server/src/server/test-utils/daemon-client.ts

@@ -265,6 +265,44 @@ export class DaemonClient {
     ); // 60 second timeout for initialization
   }
 
+  /**
+   * Initialize an agent (fetch its current state without running a prompt).
+   * This mimics what happens when clicking on an agent in the UI.
+   */
+  async initializeAgent(agentId: string): Promise<AgentSnapshotPayload> {
+    const requestId = nanoid();
+    const startPosition = this.messageQueue.length;
+
+    this.send({
+      type: "initialize_agent_request",
+      agentId,
+      requestId,
+    });
+
+    // Wait for agent_state with this agent's ID
+    return this.waitFor(
+      (msg) => {
+        if (msg.type === "agent_state" && msg.payload.id === agentId) {
+          return msg.payload;
+        }
+        return null;
+      },
+      10000,
+      { skipQueueBefore: startPosition }
+    );
+  }
+
+  /**
+   * Clear agent attention (mark as viewed).
+   * This is what happens when opening an agent that requires attention.
+   */
+  async clearAgentAttention(agentId: string): Promise<void> {
+    this.send({
+      type: "clear_agent_attention",
+      agentId,
+    });
+  }
+
   // ============================================================================
   // Agent Interaction
   // ============================================================================