feat(channel): add WeCom customer service (wechatcom_kf) channel

Introduce a new channel that integrates with WeCom Customer Service
(微信客服), separate from the existing self-built WeCom app channel.

- Register channel type `wechatcom_kf` in factory, app loader and const
- Add config keys for token / secret / aes_key / port / cursor dir and
  the first-start history-skip switch; also expose corresponding env vars
- Implement channel, message and cursor store under channel/wechatcom_kf/

Co-authored-by: Cursor <cursoragent@cursor.com>

config.py

@@ -151,6 +151,14 @@ available_setting = {
     "wechatcomapp_secret": "",  # 企业微信app的secret
     "wechatcomapp_agent_id": "",  # 企业微信app的agent_id
     "wechatcomapp_aes_key": "",  # 企业微信app的aes_key
+    # 微信客服(wechatcom_kf)的配置
+    # 注意: 微信客服与企微自建应用是两套不同的应用,共用 corp_id,但 secret/token/aes_key 各自独立
+    "wechatcom_kf_token": "",  # 微信客服回调token
+    "wechatcom_kf_port": 9899,  # 微信客服回调服务端口
+    "wechatcom_kf_secret": "",  # 微信客服应用的secret
+    "wechatcom_kf_aes_key": "",  # 微信客服回调aes_key
+    "wechatcom_kf_cursor_dir": "tmp",  # 拉取消息的cursor持久化目录(相对项目根)
+    "wechatcom_kf_skip_history_on_first_start": True,  # 首次启动(无cursor)时跳过历史消息,只拉最新
     # 飞书配置
     "feishu_port": 80,  # 飞书bot监听端口，仅webhook模式需要
     "feishu_app_id": "",  # 飞书机器人应用APP Id
@@ -174,7 +182,7 @@ available_setting = {
     # chatgpt指令自定义触发词
     "clear_memory_commands": ["#清除记忆"],  # 重置会话指令，必须以#开头
     # channel配置
-    "channel_type": "",  # 通道类型，支持多渠道同时运行。单个: "feishu"，多个: "feishu, dingtalk" 或 ["feishu", "dingtalk"]。可选值: web,feishu,dingtalk,wecom_bot,weixin,wechatmp,wechatmp_service,wechatcom_app
+    "channel_type": "",  # 通道类型，支持多渠道同时运行。单个: "feishu"，多个: "feishu, dingtalk" 或 ["feishu", "dingtalk"]。可选值: web,feishu,dingtalk,wecom_bot,weixin,wechatmp,wechatmp_service,wechatcom_app,wechatcom_kf
     "web_console": True,  # 是否自动启动Web控制台（默认启动）。设为False可禁用
     "subscribe_msg": "",  # 订阅消息, 支持: wechatmp, wechatmp_service, wechatcom_app
     "debug": False,  # 是否开启debug模式，开启后会打印更多日志
@@ -410,6 +418,10 @@ def load_config():
         "wechatmp_app_secret": "WECHATMP_APP_SECRET",
         "wechatcomapp_agent_id": "WECHATCOMAPP_AGENT_ID",
         "wechatcomapp_secret": "WECHATCOMAPP_SECRET",
+        "wechatcom_corp_id": "WECHATCOM_CORP_ID",
+        "wechatcom_kf_secret": "WECHATCOM_KF_SECRET",
+        "wechatcom_kf_token": "WECHATCOM_KF_TOKEN",
+        "wechatcom_kf_aes_key": "WECHATCOM_KF_AES_KEY",
         "qq_app_id": "QQ_APP_ID",
         "qq_app_secret": "QQ_APP_SECRET",
         "weixin_token": "WEIXIN_TOKEN",