Add WeWork XiaoAi TTS bot - WeChat Work long connection bridge

Receives messages from WeChat Work bot via WebSocket long connection
and speaks them through XiaoAi smart speaker TTS.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_ws_client.py

@@ -0,0 +1,84 @@
+import json
+import pytest
+
+from app.services.ws_client import _extract_text
+
+
+def test_extract_text_text_message():
+    msg = {
+        "cmd": "aibot_msg_callback",
+        "headers": {"req_id": "req123"},
+        "body": {
+            "msgtype": "text",
+            "text": {"content": "你好世界"},
+        },
+    }
+    assert _extract_text(msg) == "你好世界"
+
+
+def test_extract_text_voice_message():
+    msg = {
+        "cmd": "aibot_msg_callback",
+        "headers": {"req_id": "req123"},
+        "body": {
+            "msgtype": "voice",
+            "voice": {"content": "语音识别结果"},
+        },
+    }
+    assert _extract_text(msg) == "语音识别结果"
+
+
+def test_extract_text_image_returns_none():
+    msg = {
+        "cmd": "aibot_msg_callback",
+        "body": {
+            "msgtype": "image",
+            "image": {"url": "https://example.com/pic.jpg"},
+        },
+    }
+    assert _extract_text(msg) is None
+
+
+def test_extract_text_empty_content():
+    msg = {
+        "cmd": "aibot_msg_callback",
+        "body": {
+            "msgtype": "text",
+            "text": {"content": "   "},
+        },
+    }
+    assert _extract_text(msg) is None
+
+
+def test_extract_text_missing_body():
+    msg = {"cmd": "aibot_msg_callback"}
+    assert _extract_text(msg) is None
+
+
+def test_subscribe_message_format():
+    """Verify subscribe message matches documented format"""
+    msg = {
+        "cmd": "aibot_subscribe",
+        "headers": {"req_id": "test_req_id"},
+        "body": {
+            "bot_id": "test_bot_id",
+            "secret": "test_secret",
+        },
+    }
+    data = json.dumps(msg)
+    parsed = json.loads(data)
+    assert parsed["cmd"] == "aibot_subscribe"
+    assert parsed["body"]["bot_id"] == "test_bot_id"
+    assert parsed["body"]["secret"] == "test_secret"
+
+
+def test_ping_message_format():
+    """Verify ping message format matches documented format"""
+    msg = {
+        "cmd": "ping",
+        "headers": {"req_id": "test_req_id"},
+    }
+    data = json.dumps(msg)
+    parsed = json.loads(data)
+    assert parsed["cmd"] == "ping"
+    assert "req_id" in parsed["headers"]