fix(feishu): render Markdown tables via post+md instead of text downgrade

gateway/config.py

@@ -74,6 +74,21 @@ def _normalize_notice_delivery(value: Any, default: str = "public") -> str:
     return default
 
 
+def _normalize_group_model_defaults(raw: Any) -> Dict[str, str]:
+    """Coerce group_model_defaults to ``Dict[str, str]`` from config.
+
+    Strips falsy keys/values and ensures string-typed entries so downstream
+    code (gateway/run.py) can simply call ``.get(chat_id)`` without type
+    gymnastics.
+
+    / 将 config.yaml 中的 group_model_defaults 转为干净的 ``{str: str}`` 字典，
+    / 过滤空值并确保字符串类型，下游直接 ``.get(chat_id)`` 即可。
+    """
+    if not isinstance(raw, dict):
+        return {}
+    return {str(k): str(v) for k, v in raw.items() if k and v}
+
+
 def _ensure_platform_extra_dict(platforms_data: dict, name: str) -> tuple[dict, dict]:
     """Get-or-create ``platforms_data[name]`` and its nested ``extra`` dict.
 
@@ -493,6 +508,28 @@ class GatewayConfig:
     # fresh session exactly as if the reset policy had fired.  0 = disabled.
     session_store_max_age_days: int = 90
 
+    # Per-group default model overrides: {chat_id: model_name}
+    #
+    # When a message arrives from a group chat, the gateway checks this map
+    # before falling through to the global ``model.default``.  The per-session
+    # ``/model`` command still takes precedence over this (see run.py).
+    #
+    # This gives operators a three-tier model resolution:
+    #   global default  <  group default  <  per-session /model override
+    #
+    # Example config.yaml entry:
+    #   group_model_defaults:
+    #     oc_869c1d931f317119d8f51f20797b599c: deepseek-v4-flash  # 课程设计部
+    #     oc_53d22ce34646cebabf06e48ff986ee4c: mistral-large       # 自媒体部
+    #
+    # / 按群（chat_id）设置默认模型。消息来自某个群聊时，网关先查这个映射，
+    # / 再落回全局 model.default。手动 /model 覆盖优先级更高。
+    # / 由此实现三层模型解析：全局默认 < 群默认 < 会话覆盖。
+    #
+    # Bilingual note: field names and log messages stay in English for
+    # upstream compatibility; operator-facing comments are kept bilingual.
+    group_model_defaults: Dict[str, str] = field(default_factory=dict)
+
     def get_connected_platforms(self) -> List[Platform]:
         """Return list of platforms that are enabled and configured."""
         connected = []
@@ -654,6 +691,9 @@ def from_dict(cls, data: Dict[str, Any]) -> "GatewayConfig":
             unauthorized_dm_behavior=unauthorized_dm_behavior,
             streaming=StreamingConfig.from_dict(data.get("streaming", {})),
             session_store_max_age_days=session_store_max_age_days,
+            group_model_defaults=_normalize_group_model_defaults(
+                data.get("group_model_defaults")
+            ),
         )
 
     def get_unauthorized_dm_behavior(self, platform: Optional[Platform] = None) -> str:
@@ -761,6 +801,14 @@ def load_gateway_config() -> GatewayConfig:
                     "pair",
                 )
 
+            # Pass-through: group_model_defaults is a flat {chat_id: model}
+            # map defined at the top level of config.yaml.  It is consumed
+            # at runtime by _resolve_session_agent_runtime in run.py.
+            # / 透传 group_model_defaults，不做任何转换。
+            # / 运行时由 run.py 的 _resolve_session_agent_runtime 消费。
+            if "group_model_defaults" in yaml_cfg:
+                gw_data["group_model_defaults"] = yaml_cfg["group_model_defaults"]
+
             # Merge platforms section from config.yaml into gw_data so that
             # nested keys like platforms.webhook.extra.routes are loaded.
             yaml_platforms = yaml_cfg.get("platforms")

gateway/run.py

@@ -2256,6 +2256,35 @@ def _resolve_session_agent_runtime(
                 resolved_session_key = None
 
         model = _resolve_gateway_model(user_config)
+
+        # ── Per-group default model ──────────────────────────────────────
+        #
+        # If the incoming message is from a group chat, check
+        # group_model_defaults for a chat_id → model mapping BEFORE
+        # consulting per-session overrides.  This gives operators a
+        # three-tier resolution chain:
+        #
+        #   1. Global default   (config.yaml → model.default)
+        #   2. Group default    (config.yaml → group_model_defaults[chat_id])
+        #   3. Session override (/model command in a specific topic/thread)
+        #
+        # Step 3 (session override) is evaluated immediately below, so this
+        # value is a lower-priority base that gets replaced if an override
+        # exists.
+        #
+        # / 群默认模型检查。消息来自群聊时，在查会话覆盖之前先查群默认。
+        # / 优先级：全局默认 < 群默认 < 会话覆盖。
+        # / 下面紧跟着会话覆盖逻辑，所以这里的值会被覆盖掉（如果有覆盖的话）。
+        if source is not None and source.chat_id:
+            group_defaults = getattr(self.config, "group_model_defaults", None) or {}
+            group_model = group_defaults.get(str(source.chat_id))
+            if group_model:
+                logger.info(
+                    "Group model default: chat_id=%s model=%s (config was %s)",
+                    source.chat_id, group_model, model,
+                )
+                model = group_model
+
         override = self._session_model_overrides.get(resolved_session_key) if resolved_session_key else None
         if override:
             override_model = override.get("model", model)