feat(news): tune package research and add exclusive historical rechecks

backend/src/alphapulse/news_risk/contracts.py

@@ -32,6 +32,9 @@ class Correction(BaseModel):
 class PackageTimePoint(BaseModel):
     occurred_at: datetime | None = Field(description="发生时间；未知必须为null且time_precision=unknown，已知必须带时区，不用报道时间代替")
     time_precision: Literal['minute', 'day', 'month', 'unknown'] = Field(description='occurred_at为null时必须unknown；非null时按原文精度选择minute/day/month')
+    planned_at: datetime | None = Field(default=None, description='计划发生时间，不证明已发生')
+    planned_precision: Literal['minute', 'day', 'month', 'unknown'] = 'unknown'
+    period_text: str = Field(default='', description='数据统计期间原文')
     time_text: str
     reported_at: datetime | None
     description: str = Field(min_length=1)
@@ -40,6 +43,10 @@ class PackageTimePoint(BaseModel):
 
     @model_validator(mode='after')
     def time_consistency(self):
+        if (self.planned_at is None) != (self.planned_precision == 'unknown'):
+            raise ValueError('计划时间与精度不一致')
+        if self.planned_at and self.planned_at.tzinfo is None:
+            raise ValueError('计划时间必须有时区')
         if (self.occurred_at is None) != (self.time_precision == 'unknown'):
             raise ValueError('发生时间与精度不一致')
         if self.occurred_at and self.occurred_at.tzinfo is None: