fix(telegram): preserve topic metadata on overflow edits

tests/gateway/test_telegram_format.py

@@ -809,6 +809,33 @@ class TestEditMessageStreamingSafety:
         # Continuations were sent threaded as replies for visual grouping.
         assert adapter._bot.send_message.await_count == len(result.continuation_message_ids)
 
+    @pytest.mark.asyncio
+    async def test_message_too_long_continuations_preserve_topic_metadata(self):
+        """Overflow continuations should stay in the originating Telegram topic."""
+        adapter = TelegramAdapter(PlatformConfig(enabled=True, token="fake-token"))
+        adapter._bot = MagicMock()
+        adapter._bot.edit_message_text = AsyncMock()
+        sent_kwargs = []
+
+        async def _fake_send(**kwargs):
+            sent_kwargs.append(kwargs)
+            return SimpleNamespace(message_id=1000 + len(sent_kwargs))
+
+        adapter._bot.send_message = AsyncMock(side_effect=_fake_send)
+
+        result = await adapter.edit_message(
+            "-100123",
+            "456",
+            "x" * 6000,
+            finalize=False,
+            metadata={"thread_id": "17585"},
+        )
+
+        assert result.success is True
+        assert sent_kwargs, "expected at least one overflow continuation"
+        assert all(kwargs.get("message_thread_id") == 17585 for kwargs in sent_kwargs)
+        assert sent_kwargs[0]["reply_to_message_id"] == 456
+
 # =========================================================================
 # Telegram guest mention gating
 # =========================================================================