feat(modules): 帮助中心、工单、工作流与多渠道接入

补齐 FAQ、帮助中心、工单、可视化工作流及 Telegram/WhatsApp/Slack 等渠道模块。

backend/app/channels/sms/__init__.py

@@ -0,0 +1,38 @@
+"""
+Copyright 2024-2026 ChatterMate
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+from app.channels.sms.base import (
+    SmsProvider, SmsWebhookRequest, CredentialField,
+    get_provider, list_providers, register_provider,
+)
+# Import provider modules so they self-register
+from app.channels.sms import twilio  # noqa: F401
+from app.channels.sms import vonage  # noqa: F401
+from app.channels.sms import messagebird  # noqa: F401
+from app.channels.sms import plivo  # noqa: F401
+from app.channels.sms import brevo  # noqa: F401
+from app.channels.sms import sns  # noqa: F401
+# The channel adapter (registers itself for channel_type 'sms')
+from app.channels.sms import adapter  # noqa: F401
+
+__all__ = [
+    "SmsProvider",
+    "SmsWebhookRequest",
+    "CredentialField",
+    "get_provider",
+    "list_providers",
+    "register_provider",
+]