fix(telegram): last draft push is the final text so the client folds it into the message

src/beaver_gateway/frontends/telegram/drafts.py

@@ -1,5 +1,9 @@
 """One ``sendMessageDraft`` stream per running turn (§3.8).
 
+The client folds a draft into the message that follows only when their
+texts are identical - so the last push is the final text itself, rendered
+exactly as the outbox will send it, with no status line.
+
 A draft is ephemeral and lives 30 s, Telegram throttles edits to about one
 per second per chat, and thinking or a tool call would otherwise look like a
 hang - so the draft opens with a status line straight away, is refreshed on
@@ -74,15 +78,29 @@ class Draft:
         The final ``sendMessage`` must reach Telegram after the last draft,
         or the draft lands on top of the message and lingers for its 30 s.
         """
-        if self._task is None:
-            return
-        self._task.cancel()
-        with contextlib.suppress(asyncio.CancelledError):
-            await self._task
-        self._task = None
+        if self._task is not None:
+            self._task.cancel()
+            await asyncio.gather(self._task, return_exceptions=True)
+            self._task = None
         if self._inflight is not None:
             with contextlib.suppress(Exception):
                 await self._inflight
+            self._inflight = None
+
+    async def finish(self, text: str) -> None:
+        """Last push: the final text verbatim, so the message replaces the draft."""
+        await self.stop()
+        if self._broken or not text.strip():
+            return
+        try:
+            try:
+                await self._send(to_html(text), "HTML")
+            except TelegramBadRequest:
+                await self._send(text, None)
+        except TelegramAPIError as exc:
+            _log.warning(
+                "final draft to %s/%s failed: %s", self._chat_id, self._thread_id, exc
+            )
 
     async def _run(self) -> None:
         while not self._broken: