fix: start typing on partial deltas

src/auto-reply/reply/agent-runner.heartbeat-typing.test.ts

@@ -145,6 +145,23 @@ describe("runReplyAgent typing (heartbeat)", () => {
     expect(typing.startTypingLoop).toHaveBeenCalled();
   });
 
+  it("signals typing even without consumer partial handler", async () => {
+    runEmbeddedPiAgentMock.mockImplementationOnce(
+      async (params: EmbeddedPiAgentParams) => {
+        await params.onPartialReply?.({ text: "hi" });
+        return { payloads: [{ text: "final" }], meta: {} };
+      },
+    );
+
+    const { run, typing } = createMinimalRun({
+      typingMode: "message",
+    });
+    await run();
+
+    expect(typing.startTypingOnText).toHaveBeenCalledWith("hi");
+    expect(typing.startTypingLoop).not.toHaveBeenCalled();
+  });
+
   it("never signals typing for heartbeat runs", async () => {
     const onPartialReply = vi.fn();
     runEmbeddedPiAgentMock.mockImplementationOnce(