feat(beaver): 完成Task Team功能v1实现，重构后端架构支持统一内核

新增内部Task系统，包括验证、反馈门控机制，实现自动质量验证
(通过率>=0.75)和用户反馈闭环(satisfied/revise/abandon)。

实现Agent Team v1协调器，支持sequence/parallel/dag执行策略，
sub-agent复用主AgentLoop，每个run使用独立memory snapshot。

建立Skill学习pipeline，包含draft/审核/发布/回滚完整生命周期，
通过Task验证通过且用户满意才生成学习候选。

重构目录结构，移除third_party依赖，建立统一engine内核，
所有agent共享运行时基础组件。

更新ContextBuilder清理provider消息字段，增强SkillContext版本管理，
集成TaskExecutionPlanner和TaskSkillResolver实现技能解析机制。

app-instance/backend/beaver/interfaces/web/schemas/__init__.py

@@ -1,11 +1,25 @@
 """Web request and response schemas."""
 
-from .chat import WebChatRequest, WebChatResponse, WebErrorResponse, WebProviderTarget, WebStatusResponse
+from .chat import (
+    WebChatFeedbackRequest,
+    WebChatFeedbackResponse,
+    WebChatRequest,
+    WebChatResponse,
+    WebErrorResponse,
+    WebProviderConfigRequest,
+    WebProviderConfigResponse,
+    WebProviderTarget,
+    WebStatusResponse,
+)
 
 __all__ = [
+    "WebChatFeedbackRequest",
+    "WebChatFeedbackResponse",
     "WebChatRequest",
     "WebChatResponse",
     "WebErrorResponse",
+    "WebProviderConfigRequest",
+    "WebProviderConfigResponse",
     "WebProviderTarget",
     "WebStatusResponse",
 ]

app-instance/backend/beaver/interfaces/web/schemas/chat.py

@@ -77,6 +77,47 @@ class WebChatResponse(BaseModel):
     provider_name: str | None = None
     model: str | None = None
     usage: dict[str, Any] = Field(default_factory=dict)
+    task_id: str | None = None
+    task_status: str | None = None
+    validation_result: dict[str, Any] | None = None
+
+
+class WebChatFeedbackRequest(BaseModel):
+    """Feedback on the latest assistant result in chat."""
+
+    session_id: str
+    run_id: str
+    feedback_type: str
+    comment: str | None = None
+
+
+class WebChatFeedbackResponse(BaseModel):
+    """Feedback recording result."""
+
+    session_id: str
+    run_id: str
+    task_id: str
+    task_status: str
+    feedback_type: str
+    learning_candidates: list[dict[str, Any]] = Field(default_factory=list)
+
+
+class WebProviderConfigRequest(BaseModel):
+    """Provider config update from the status page."""
+
+    enabled: bool = True
+    model: str | None = None
+    api_key: str | None = None
+    api_base: str | None = None
+    request_timeout_seconds: float | None = None
+
+
+class WebProviderConfigResponse(BaseModel):
+    """Provider config update result."""
+
+    ok: bool
+    provider: str
+    enabled: bool
 
 
 class WebStatusResponse(BaseModel):