test(telegram): cover rich message fallback latch

tests/channels/test_telegram_channel.py

@@ -466,6 +466,45 @@ async def test_send_text_gives_up_after_max_retries() -> None:
     assert channel._app.bot.sent_messages == []
 
 
+@pytest.mark.asyncio
+async def test_send_rich_capability_error_latches_and_falls_back() -> None:
+    from telegram.error import BadRequest
+
+    channel = TelegramChannel(
+        TelegramConfig(enabled=True, token="123:abc", allow_from=["*"]),
+        MessageBus(),
+    )
+    channel._app = _FakeApp(lambda: None)
+    channel._app.bot.do_api_request = AsyncMock(side_effect=BadRequest("Method not found"))
+
+    await channel.send(OutboundMessage(channel="telegram", chat_id="123", content="**hello**"))
+
+    assert channel._rich_send_disabled is True
+    channel._app.bot.do_api_request.assert_awaited_once()
+    assert len(channel._app.bot.sent_messages) == 1
+    assert channel._app.bot.sent_messages[0]["text"]
+
+
+@pytest.mark.asyncio
+async def test_send_rich_bad_request_does_not_latch_capability() -> None:
+    from telegram.error import BadRequest
+
+    channel = TelegramChannel(
+        TelegramConfig(enabled=True, token="123:abc", allow_from=["*"]),
+        MessageBus(),
+    )
+    channel._app = _FakeApp(lambda: None)
+    channel._app.bot.do_api_request = AsyncMock(
+        side_effect=BadRequest("Bad Request: message to reply not found")
+    )
+
+    await channel.send(OutboundMessage(channel="telegram", chat_id="123", content="**hello**"))
+
+    assert channel._rich_send_disabled is False
+    channel._app.bot.do_api_request.assert_awaited_once()
+    assert len(channel._app.bot.sent_messages) == 1
+
+
 @pytest.mark.asyncio
 async def test_on_error_logs_network_issues_as_warning(monkeypatch) -> None:
     from telegram.error import NetworkError