fix: harden block stream dedupe

src/agents/pi-embedded-subscribe.test.ts

@@ -231,6 +231,99 @@ describe("subscribeEmbeddedPiSession", () => {
     expect(subscription.assistantTexts).toEqual(["Hello block"]);
   });
 
+  it("does not duplicate when text_end repeats full content", () => {
+    let handler: ((evt: unknown) => void) | undefined;
+    const session: StubSession = {
+      subscribe: (fn) => {
+        handler = fn;
+        return () => {};
+      },
+    };
+
+    const onBlockReply = vi.fn();
+
+    const subscription = subscribeEmbeddedPiSession({
+      session: session as unknown as Parameters<
+        typeof subscribeEmbeddedPiSession
+      >[0]["session"],
+      runId: "run",
+      onBlockReply,
+      blockReplyBreak: "text_end",
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: "Good morning!",
+      },
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_end",
+        content: "Good morning!",
+      },
+    });
+
+    expect(onBlockReply).toHaveBeenCalledTimes(1);
+    expect(subscription.assistantTexts).toEqual(["Good morning!"]);
+  });
+
+  it("does not duplicate block chunks when text_end repeats full content", () => {
+    let handler: ((evt: unknown) => void) | undefined;
+    const session: StubSession = {
+      subscribe: (fn) => {
+        handler = fn;
+        return () => {};
+      },
+    };
+
+    const onBlockReply = vi.fn();
+
+    subscribeEmbeddedPiSession({
+      session: session as unknown as Parameters<
+        typeof subscribeEmbeddedPiSession
+      >[0]["session"],
+      runId: "run",
+      onBlockReply,
+      blockReplyBreak: "text_end",
+      blockReplyChunking: {
+        minChars: 5,
+        maxChars: 40,
+        breakPreference: "newline",
+      },
+    });
+
+    const fullText = "First line\nSecond line\nThird line\n";
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: fullText,
+      },
+    });
+
+    const callsAfterDelta = onBlockReply.mock.calls.length;
+    expect(callsAfterDelta).toBeGreaterThan(0);
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_end",
+        content: fullText,
+      },
+    });
+
+    expect(onBlockReply).toHaveBeenCalledTimes(callsAfterDelta);
+  });
+
   it("streams soft chunks with paragraph preference", () => {
     let handler: ((evt: unknown) => void) | undefined;
     const session: StubSession = {