Initial commit: KPI Management System Backend

Features:
- FastAPI backend with JWT authentication
- MySQL database with SQLAlchemy ORM
- KPI workflow: draft → pending → approved → evaluation → completed
- Ollama LLM API integration for AI features
- Gitea API integration for version control
- Complete API endpoints for KPI, dashboard, notifications

Tables: KPI_D_* prefix naming convention

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/models/kpi_sheet.py

@@ -0,0 +1,103 @@
+"""
+KPI 表單 Model
+"""
+from datetime import datetime
+from decimal import Decimal
+from typing import Optional, List, TYPE_CHECKING
+
+from sqlalchemy import String, Integer, DateTime, Text, Numeric, ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.core.database import Base
+
+if TYPE_CHECKING:
+    from app.models.employee import Employee
+    from app.models.kpi_period import KPIPeriod
+    from app.models.department import Department
+    from app.models.kpi_item import KPIItem
+    from app.models.kpi_review_log import KPIReviewLog
+
+
+# KPI 表單狀態
+class KPISheetStatus:
+    DRAFT = "draft"              # 草稿
+    PENDING = "pending"          # 待審核
+    APPROVED = "approved"        # 已核准
+    SELF_EVAL = "self_eval"      # 自評中
+    MANAGER_EVAL = "manager_eval"  # 主管評核中
+    COMPLETED = "completed"      # 已完成
+    SETTLED = "settled"          # 已結算
+
+
+# 狀態轉換規則
+VALID_STATUS_TRANSITIONS = {
+    KPISheetStatus.DRAFT: [KPISheetStatus.PENDING],
+    KPISheetStatus.PENDING: [KPISheetStatus.APPROVED, KPISheetStatus.DRAFT],
+    KPISheetStatus.APPROVED: [KPISheetStatus.SELF_EVAL],
+    KPISheetStatus.SELF_EVAL: [KPISheetStatus.MANAGER_EVAL],
+    KPISheetStatus.MANAGER_EVAL: [KPISheetStatus.COMPLETED],
+    KPISheetStatus.COMPLETED: [KPISheetStatus.SETTLED],
+    KPISheetStatus.SETTLED: [],
+}
+
+
+class KPISheet(Base):
+    """KPI 表單"""
+
+    __tablename__ = "KPI_D_sheets"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    employee_id: Mapped[int] = mapped_column(ForeignKey("KPI_D_employees.id"), nullable=False)
+    period_id: Mapped[int] = mapped_column(ForeignKey("KPI_D_periods.id"), nullable=False)
+    department_id: Mapped[int] = mapped_column(ForeignKey("KPI_D_departments.id"), nullable=False)
+    status: Mapped[str] = mapped_column(String(20), default=KPISheetStatus.DRAFT)
+
+    # 提交資訊
+    submitted_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
+
+    # 審核資訊
+    approved_by: Mapped[Optional[int]] = mapped_column(ForeignKey("KPI_D_employees.id"))
+    approved_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
+    approve_comment: Mapped[Optional[str]] = mapped_column(Text)
+
+    # 退回資訊
+    rejected_by: Mapped[Optional[int]] = mapped_column(ForeignKey("KPI_D_employees.id"))
+    rejected_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
+    reject_reason: Mapped[Optional[str]] = mapped_column(Text)
+
+    # 自評資訊
+    self_eval_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
+
+    # 主管評核資訊
+    manager_eval_by: Mapped[Optional[int]] = mapped_column(ForeignKey("KPI_D_employees.id"))
+    manager_eval_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
+    manager_eval_comment: Mapped[Optional[str]] = mapped_column(Text)
+
+    # 分數
+    total_score: Mapped[Optional[Decimal]] = mapped_column(Numeric(5, 4))
+
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    # Relationships
+    employee: Mapped["Employee"] = relationship(
+        "Employee", back_populates="kpi_sheets", foreign_keys=[employee_id]
+    )
+    period: Mapped["KPIPeriod"] = relationship("KPIPeriod", back_populates="kpi_sheets")
+    department: Mapped["Department"] = relationship("Department")
+    items: Mapped[List["KPIItem"]] = relationship(
+        "KPIItem", back_populates="sheet", cascade="all, delete-orphan"
+    )
+    review_logs: Mapped[List["KPIReviewLog"]] = relationship(
+        "KPIReviewLog", back_populates="sheet", cascade="all, delete-orphan"
+    )
+    approver: Mapped[Optional["Employee"]] = relationship("Employee", foreign_keys=[approved_by])
+    rejecter: Mapped[Optional["Employee"]] = relationship("Employee", foreign_keys=[rejected_by])
+    manager_evaluator: Mapped[Optional["Employee"]] = relationship("Employee", foreign_keys=[manager_eval_by])
+
+    def can_transition_to(self, new_status: str) -> bool:
+        """檢查是否可以轉換到指定狀態"""
+        return new_status in VALID_STATUS_TRANSITIONS.get(self.status, [])
+
+    def __repr__(self) -> str:
+        return f"<KPISheet id={self.id} employee={self.employee_id} period={self.period_id} status={self.status}>"