fix(telegram): escape dynamic markdown in callback flows

Use MarkdownV2 formatting for Telegram callback follow-ups and interactive prompts where dynamic names or user text can break legacy Markdown parsing. Add regression coverage for reload-mcp, model picker, approval callbacks, and update prompts.

tests/gateway/test_telegram_model_picker.py

@@ -43,6 +43,65 @@ def _make_adapter():
 
 
 class TestTelegramModelPicker:
+    @pytest.mark.asyncio
+    async def test_send_model_picker_escapes_dynamic_provider_label(self):
+        adapter = _make_adapter()
+        sent = {}
+
+        async def mock_send_message(**kwargs):
+            sent.update(kwargs)
+            return SimpleNamespace(message_id=101)
+
+        adapter._bot.send_message = AsyncMock(side_effect=mock_send_message)
+
+        result = await adapter.send_model_picker(
+            chat_id="12345",
+            providers=[
+                {"slug": "provider_one", "name": "Provider One", "total_models": 1, "is_current": True}
+            ],
+            current_model="model_1",
+            current_provider="provider_one",
+            session_key="s",
+            on_model_selected=AsyncMock(),
+            metadata={"thread_id": "99999"},
+        )
+
+        assert result.success is True
+        assert "MARKDOWN_V2" in repr(sent["parse_mode"])
+        assert "provider\\_one" in sent["text"]
+        assert "`model_1`" in sent["text"]
+
+    @pytest.mark.asyncio
+    async def test_back_button_escapes_dynamic_provider_label(self):
+        adapter = _make_adapter()
+        adapter._model_picker_state["12345"] = {
+            "providers": [{"slug": "provider_one", "name": "Provider One", "total_models": 1, "is_current": True}],
+            "current_model": "model_1",
+            "current_provider": "provider_one",
+            "session_key": "s",
+            "on_model_selected": AsyncMock(),
+            "msg_id": 42,
+        }
+
+        query = AsyncMock()
+        query.data = "mb"
+        query.message = MagicMock()
+        query.message.chat_id = 12345
+        query.from_user = MagicMock()
+        query.answer = AsyncMock()
+        query.edit_message_text = AsyncMock()
+
+        update = MagicMock()
+        update.callback_query = query
+        context = MagicMock()
+
+        await adapter._handle_model_picker_callback(query, "mb", "12345")
+
+        edit_kwargs = query.edit_message_text.call_args[1]
+        assert "MARKDOWN_V2" in repr(edit_kwargs["parse_mode"])
+        assert "provider\\_one" in edit_kwargs["text"]
+        assert "`model_1`" in edit_kwargs["text"]
+
     @pytest.mark.asyncio
     async def test_retries_without_thread_when_thread_not_found(self):
         adapter = _make_adapter()