feat(KR): KR完整修复 — krs表打通+方向符号operator+权重自由输入

- 后端okr.py: KR读取从ActionPlan改为krs表, 新增KR CRUD API(POST/PUT/DELETE /okr/{objective_id}/krs) + 批量sync
- operator方向符号: krs表加operator/tolerance/weight/sort_order/monthly_milestones列
- progress方向感知计算(>=/>: current/target, <=/<: target/current, =: 容差), 达成→status=achieved
- 关联KPI自动继承方向(threshold_green解析: F_COST_RATIO<=18等)
- maps.py: 保存地图时自动同步objectives+krs表, JSON→krs数据迁移脚本
- 前端: 权重下拉改自由数字输入(可小数33.33) + 方向选择器(≥/≤/>/</=) + 自动平分按钮 + KPI方向继承提示
- pytest: 10个新测试(krs CRUD/方向感知/权重校验/多租户隔离) + 更新旧KR测试
- 迁移: 现有strategic_maps JSON 12条KR已写入krs表

backend/app/models/__init__.py

@@ -750,9 +750,14 @@ class KR(Base):
     objective_id = Column(Integer, ForeignKey("objectives.id"), nullable=False, comment="OKR目标ID")
     title = Column(String(200), nullable=False, comment="KR标题")
     metric_kpi_id = Column(Integer, ForeignKey("kpi_definitions.id"), nullable=True, comment="度量KPI ID")
+    operator = Column(String(5), default=">=", nullable=False, comment="方向符号: >=/<=/>/</= (KR完整修复 2026-08-27)")
+    tolerance = Column(Numeric(10, 4), nullable=True, comment="容差(仅=时使用)")
+    weight = Column(Numeric(5, 2), nullable=True, comment="KR权重%")
     target_value = Column(Numeric(15, 2), nullable=True, comment="目标值")
     current_value = Column(Numeric(15, 2), nullable=True, comment="当前值")
     progress = Column(Integer, default=0, comment="完成进度 0-100")
-    status = Column(String(20), default="pending", comment="pending/in_progress/completed/cancelled")
+    status = Column(String(20), default="pending", comment="pending/in_progress/completed/cancelled/achieved")
     due_date = Column(Date, nullable=True, comment="截止日期")
+    monthly_milestones = Column(JSON, nullable=True, comment="月度里程碑: [{\"month\":\"2026-07\",\"label\":\"...\",\"status\":\"completed\"}]")
+    sort_order = Column(Integer, default=0, comment="排序")
     created_at = Column(DateTime, server_default=func.now())