feat: add cumulative checkin tracking mode for goals

Goals can now choose between milestone-based progress (existing) and
cumulative checkin-based progress (new). Cumulative mode supports
cross-unit conversion (e.g. kcal → g fat) via a configurable
conversion rate. New GoalCheckin model stores daily inputs; progress
auto-recalculates on every checkin C/U/D. Backup import/export covers
the new table. Frontend GoalDialog, GoalDetailPage and GoalPage cards
adapt to show cumulative progress or milestone progress based on
track_type.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

api/app/models/__init__.py

@@ -4,7 +4,7 @@ from app.models.tag import Tag, task_tags
 from app.models.user_settings import UserSettings
 from app.models.habit import HabitGroup, Habit, HabitCheckin
 from app.models.anniversary import AnniversaryCategory, Anniversary
-from app.models.goal import Goal, GoalStep, GoalReview, goal_tasks
+from app.models.goal import Goal, GoalStep, GoalReview, GoalCheckin, goal_tasks
 from app.models.sync_settings import SyncSettings
 from app.models.certificate import Certificate, CertificateCategory
 
@@ -12,7 +12,7 @@ __all__ = [
     "Task", "Category", "Tag", "task_tags", "UserSettings",
     "HabitGroup", "Habit", "HabitCheckin",
     "AnniversaryCategory", "Anniversary",
-    "Goal", "GoalStep", "GoalReview", "goal_tasks",
+    "Goal", "GoalStep", "GoalReview", "GoalCheckin", "goal_tasks",
     "SyncSettings",
     "Certificate", "CertificateCategory",
 ]

api/app/models/goal.py

@@ -1,5 +1,5 @@
 import uuid as _uuid
-from sqlalchemy import Column, Integer, String, Text, Date, DateTime, Boolean, ForeignKey, Table, desc
+from sqlalchemy import Column, Integer, String, Text, Date, DateTime, Boolean, Float, ForeignKey, Table, desc
 from sqlalchemy.orm import relationship
 from app.database import Base
 from app.utils.datetime import utcnow
@@ -23,7 +23,13 @@ class Goal(Base):
     title = Column(String(200), nullable=False)
     description = Column(Text, nullable=True)
     status = Column(String(20), default="active")  # active/paused/completed/abandoned
-    progress = Column(Integer, default=0)  # 0-100，从里程碑自动计算
+    track_type = Column(String(20), default="milestone")  # "milestone" | "cumulative"
+    progress = Column(Integer, default=0)  # 0-100，里程碑模式从里程碑自动计算，累计模式从打卡汇总计算
+    target_value = Column(Float, nullable=True)  # 累计模式：目标值（目标单位）
+    target_unit = Column(String(20), nullable=True)  # 累计模式：目标单位，如 "g"、"kg"
+    input_unit = Column(String(20), nullable=True)  # 累计模式：打卡输入单位，如 "kcal"、"次"
+    conversion_rate = Column(Float, default=1.0)  # 累计模式：换算率（多少输入单位 = 1 目标单位）
+    current_value = Column(Float, default=0)  # 累计模式：累计打卡值（输入单位）
     target_date = Column(Date, nullable=True)
     completed_at = Column(DateTime, nullable=True)
     category_id = Column(Integer, ForeignKey("categories.id"), nullable=True)
@@ -47,6 +53,11 @@ class Goal(Base):
         cascade="all, delete-orphan",
         order_by=lambda: desc(GoalReview.created_at),
     )
+    checkins = relationship(
+        "GoalCheckin", back_populates="goal",
+        cascade="all, delete-orphan",
+        order_by=lambda: desc(GoalCheckin.checkin_date),
+    )
     tasks = relationship("Task", secondary=goal_tasks, back_populates="goals")
 
 
@@ -88,3 +99,21 @@ class GoalReview(Base):
 
     # 关联关系
     goal = relationship("Goal", back_populates="reviews")
+
+
+class GoalCheckin(Base):
+    """目标累计打卡记录模型"""
+    __tablename__ = "goal_checkins"
+
+    id = Column(Integer, primary_key=True, index=True)
+    uuid = Column(String(36), default=lambda: str(_uuid.uuid4()), unique=True, index=True)
+    goal_id = Column(Integer, ForeignKey("goals.id"), nullable=False)
+    value = Column(Float, nullable=False)
+    note = Column(Text, nullable=True)
+    checkin_date = Column(Date, nullable=False)
+    is_deleted = Column(Boolean, default=False)
+    sync_version = Column(Integer, default=1)
+    created_at = Column(DateTime, default=utcnow)
+
+    # 关联关系
+    goal = relationship("Goal", back_populates="checkins")