feat(channels/feishu): add domain config for Lark global support

Add 'domain' field to FeishuConfig (Literal['feishu', 'lark'], default 'feishu').
Pass domain to lark.Client.builder() and lark.ws.Client to support Lark global
(open.larksuite.com) in addition to Feishu China (open.feishu.cn).
Existing configs default to 'feishu' for backward compatibility.

Also add documentation for domain field in README.md and add tests for
domain config.

nanobot/channels/feishu.py

@@ -22,6 +22,8 @@ from nanobot.channels.base import BaseChannel
 from nanobot.config.paths import get_media_dir
 from nanobot.config.schema import Base
 
+from lark_oapi.core.const import FEISHU_DOMAIN, LARK_DOMAIN
+
 FEISHU_AVAILABLE = importlib.util.find_spec("lark_oapi") is not None
 
 # Message type display mapping
@@ -255,6 +257,7 @@ class FeishuConfig(Base):
     group_policy: Literal["open", "mention"] = "mention"
     reply_to_message: bool = False  # If True, bot replies quote the user's original message
     streaming: bool = True
+    domain: Literal["feishu", "lark"] = "feishu"  # Set to "lark" for international Lark
 
 
 _STREAM_ELEMENT_ID = "streaming_md"
@@ -328,10 +331,12 @@ class FeishuChannel(BaseChannel):
         self._loop = asyncio.get_running_loop()
 
         # Create Lark client for sending messages
+        domain = LARK_DOMAIN if self.config.domain == "lark" else FEISHU_DOMAIN
         self._client = (
             lark.Client.builder()
             .app_id(self.config.app_id)
             .app_secret(self.config.app_secret)
+            .domain(domain)
             .log_level(lark.LogLevel.INFO)
             .build()
         )
@@ -359,6 +364,7 @@ class FeishuChannel(BaseChannel):
         self._ws_client = lark.ws.Client(
             self.config.app_id,
             self.config.app_secret,
+            domain=domain,
             event_handler=event_handler,
             log_level=lark.LogLevel.INFO,
         )