story-kit: merge 227_bug_thinking_traces_visible_in_agents_panel_in_release_builds_only

frontend/src/components/AgentPanel.test.tsx

@@ -312,10 +312,11 @@ describe("Thinking traces hidden from agent stream UI", () => {
 		// AC1: no thinking block
 		expect(screen.queryByTestId("thinking-block")).not.toBeInTheDocument();
 
-		// AC2+AC3: output area renders the text
+		// AC2+AC3: output area renders the text but NOT thinking text
 		const outputArea = screen.getByTestId("agent-output-coder-1");
 		expect(outputArea).toBeInTheDocument();
 		expect(outputArea.textContent).toContain("Here is the result.");
+		expect(outputArea.textContent).not.toContain("thinking deeply");
 	});
 
 	// AC3: output-only event stream (no thinking) still works

frontend/src/components/AgentPanel.tsx

@@ -175,6 +175,9 @@ export function AgentPanel({
 									terminalAt: current.terminalAt ?? Date.now(),
 								},
 							};
+						case "thinking":
+							// Thinking traces are internal model state — never display them.
+							return prev;
 						default:
 							return prev;
 					}