feat(engine): 添加运行时上下文支持并重构工具迭代限制

添加 RuntimeContext 类用于捕获模型运行时的日期时间信息，
包括UTC时间、本地时间和时区信息，并在系统提示中显示这些信息。

同时增加最大上下文消息数和工具迭代次数的配置选项，
将验证服务从引擎加载器中移除，并更新相关的数据结构和接口。

BREAKING CHANGE: 移除了验证服务，相关字段被替换为证据状态和接受状态。

- 添加 RuntimeContext 类和相关渲染方法
- 增加 max_context_messages 和 max_tool_iterations 配置
- 移除 ValidationService 相关代码
- 更新消息记录中的验证状态字段
- 添加原始工具调用检测和回退处理

app-instance/backend/beaver/tasks/models.py

@@ -1,4 +1,4 @@
-"""Models for internal task tracking and validation."""
+"""Models for internal task tracking and user acceptance."""
 
 from __future__ import annotations
 
@@ -9,7 +9,12 @@ from typing import Any, Literal
 ValidationStatus = Literal["accepted", "rejected", "insufficient_evidence", "validator_error"]
 
 VALIDATION_STATUSES = {"accepted", "rejected", "insufficient_evidence", "validator_error"}
-TASK_OPEN_STATUSES = {"open", "running", "validating", "awaiting_feedback", "needs_review", "needs_revision"}
+TASK_OPEN_STATUSES = {"open", "running", "awaiting_acceptance", "needs_revision"}
+LEGACY_STATUS_MAP = {
+    "validating": "running",
+    "awaiting_feedback": "awaiting_acceptance",
+    "needs_review": "awaiting_acceptance",
+}
 
 
 @dataclass(slots=True)
@@ -113,11 +118,11 @@ class TaskRecord:
 
     @property
     def is_execution_active(self) -> bool:
-        return self.status in {"running", "validating"}
+        return self.status == "running"
 
     @property
     def requires_user_action(self) -> bool:
-        return self.status in {"awaiting_feedback", "needs_review", "needs_revision"}
+        return self.status in {"awaiting_acceptance", "needs_revision"}
 
     def to_dict(self) -> dict[str, Any]:
         return {
@@ -137,6 +142,7 @@ class TaskRecord:
             "satisfaction": self.satisfaction,
             "run_ids": list(self.run_ids),
             "skill_names": list(self.skill_names),
+            "acceptance": list(self.feedback),
             "feedback": list(self.feedback),
             "validation_result": self.validation_result,
             "metadata": dict(self.metadata),
@@ -152,7 +158,7 @@ class TaskRecord:
             goal=str(payload.get("goal") or payload.get("description") or ""),
             constraints=[str(item) for item in payload.get("constraints") or []],
             priority=int(payload.get("priority", 0) or 0),
-            status=str(payload.get("status") or "open"),
+            status=LEGACY_STATUS_MAP.get(str(payload.get("status") or "open"), str(payload.get("status") or "open")),
             creator=str(payload.get("creator") or "main-agent"),
             created_at=str(payload.get("created_at") or ""),
             updated_at=str(payload.get("updated_at") or ""),
@@ -161,7 +167,11 @@ class TaskRecord:
             satisfaction=_optional_float(payload.get("satisfaction")),
             run_ids=[str(item) for item in payload.get("run_ids") or []],
             skill_names=[str(item) for item in payload.get("skill_names") or []],
-            feedback=[dict(item) for item in payload.get("feedback") or [] if isinstance(item, dict)],
+            feedback=[
+                _normalize_acceptance_entry(dict(item))
+                for item in (payload.get("acceptance") or payload.get("feedback") or [])
+                if isinstance(item, dict)
+            ],
             validation_result=dict(payload["validation_result"]) if isinstance(payload.get("validation_result"), dict) else None,
             metadata=dict(payload.get("metadata") or {}),
         )
@@ -226,3 +236,13 @@ def _optional_float(value: Any) -> float | None:
     if value in (None, ""):
         return None
     return float(value)
+
+
+def _normalize_acceptance_entry(entry: dict[str, Any]) -> dict[str, Any]:
+    if entry.get("acceptance_type") is None and entry.get("feedback_type") is not None:
+        feedback_type = str(entry.get("feedback_type") or "")
+        entry["acceptance_type"] = "accept" if feedback_type == "satisfied" else feedback_type
+    if entry.get("feedback_type") is None and entry.get("acceptance_type") is not None:
+        acceptance_type = str(entry.get("acceptance_type") or "")
+        entry["feedback_type"] = "satisfied" if acceptance_type == "accept" else acceptance_type
+    return entry