fix(telegram): only retain on sendMayHaveLanded when prior preview is visible

When no prior message exists (first preview creation), prefer fallback
over silence — a duplicate is better than the user seeing nothing.
Gate sendMayHaveLanded retention on lane.hasStreamedMessage.

src/telegram/lane-delivery-text-deliverer.ts

@@ -365,13 +365,9 @@ export function createLaneTextDeliverer(params: CreateLaneTextDelivererParams) {
         context,
       });
       if (typeof previewTargetAfterStop.previewMessageId !== "number") {
-        if (lane.stream?.sendMayHaveLanded?.()) {
-          params.log(
-            `telegram: ${laneName} preview send may have landed despite missing message id; keeping to avoid duplicate`,
-          );
-          params.markDelivered();
-          return "retained";
-        }
+        // This is the first preview creation — no prior visible message exists.
+        // Even if sendMayHaveLanded, prefer fallback over silence: a duplicate
+        // is better than the user seeing nothing at all.
         return "fallback";
       }
       return finalizePreview(previewTargetAfterStop.previewMessageId, true, false);
@@ -386,7 +382,9 @@ export function createLaneTextDeliverer(params: CreateLaneTextDelivererParams) {
       context,
     });
     if (typeof previewTargetAfterStop.previewMessageId !== "number") {
-      if (lane.stream?.sendMayHaveLanded?.()) {
+      // Only retain when a prior preview is already visible to the user —
+      // otherwise falling back is safer than silence.
+      if (lane.hasStreamedMessage && lane.stream?.sendMayHaveLanded?.()) {
         params.log(
           `telegram: ${laneName} preview send may have landed despite missing message id; keeping to avoid duplicate`,
         );

src/telegram/lane-delivery.test.ts

@@ -538,10 +538,10 @@ describe("createLaneTextDeliverer", () => {
     );
   });
 
-  it("retains preview when sendMayHaveLanded is true and no messageId", async () => {
+  it("falls back when sendMayHaveLanded is true but no prior visible preview exists", async () => {
     const stream = createTestDraftStream();
     stream.sendMayHaveLanded.mockReturnValue(true);
-    // No messageId → resolvePreviewTarget returns undefined
+    // No messageId and no prior preview → nothing visible for user to see
     const harness = createHarness({ answerStream: stream });
 
     const result = await harness.deliverLaneText({
@@ -551,6 +551,34 @@ describe("createLaneTextDeliverer", () => {
       infoKind: "final",
     });
 
+    // Prefer fallback (possible duplicate) over silence (no message at all)
+    expect(result).toBe("sent");
+    expect(harness.sendPayload).toHaveBeenCalledWith(
+      expect.objectContaining({ text: "Hello final" }),
+    );
+  });
+
+  it("retains when sendMayHaveLanded is true and a prior preview was visible", async () => {
+    // Stream has a messageId (visible preview) but loses it after stop
+    const stream = createTestDraftStream({ messageId: 999 });
+    stream.sendMayHaveLanded.mockReturnValue(true);
+    const harness = createHarness({
+      answerStream: stream,
+      answerHasStreamedMessage: true,
+    });
+    // Simulate messageId lost after stop (e.g. forceNewMessage or timeout)
+    harness.stopDraftLane.mockImplementation(async (lane: DraftLaneState) => {
+      stream.setMessageId(undefined);
+      await lane.stream?.stop();
+    });
+
+    const result = await harness.deliverLaneText({
+      laneName: "answer",
+      text: "Hello final",
+      payload: { text: "Hello final" },
+      infoKind: "final",
+    });
+
     expect(result).toBe("preview-retained");
     expect(harness.sendPayload).not.toHaveBeenCalled();
     expect(harness.log).toHaveBeenCalledWith(