fix: clean telegram draft preview on dispatch errors

src/telegram/bot-message-dispatch.test.ts

@@ -687,6 +687,20 @@ describe("dispatchTelegramMessage draft streaming", () => {
     expect(draftStream.clear).toHaveBeenCalledTimes(1);
   });
 
+  it("clears preview when dispatcher throws before fallback phase", async () => {
+    const draftStream = createDraftStream(999);
+    createTelegramDraftStream.mockReturnValue(draftStream);
+    dispatchReplyWithBufferedBlockDispatcher.mockRejectedValue(new Error("dispatcher exploded"));
+
+    await expect(dispatchWithContext({ context: createContext() })).rejects.toThrow(
+      "dispatcher exploded",
+    );
+
+    expect(draftStream.stop).toHaveBeenCalledTimes(1);
+    expect(draftStream.clear).toHaveBeenCalledTimes(1);
+    expect(deliverReplies).not.toHaveBeenCalled();
+  });
+
   it("supports concurrent dispatches with independent previews", async () => {
     const draftA = createDraftStream(11);
     const draftB = createDraftStream(22);

src/telegram/bot-message-dispatch.ts

@@ -312,6 +312,7 @@ export const dispatchTelegramMessage = async ({
   };
 
   let queuedFinal = false;
+  let dispatchError: unknown;
   try {
     ({ queuedFinal } = await dispatchReplyWithBufferedBlockDispatcher({
       ctx: ctxPayload,
@@ -487,12 +488,15 @@ export const dispatchTelegramMessage = async ({
         onModelSelected,
       },
     }));
+  } catch (err) {
+    dispatchError = err;
   } finally {
     await draftStream?.stop();
   }
   let sentFallback = false;
   try {
     if (
+      !dispatchError &&
       !deliveryState.delivered &&
       (deliveryState.skippedNonSilent > 0 || deliveryState.failedDeliveries > 0)
     ) {
@@ -505,6 +509,9 @@ export const dispatchTelegramMessage = async ({
   } finally {
     await clearDraftPreviewIfNeeded();
   }
+  if (dispatchError) {
+    throw dispatchError;
+  }
 
   const hasFinalResponse = queuedFinal || sentFallback;
   if (!hasFinalResponse) {