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_period.py

@@ -0,0 +1,63 @@
+"""
+KPI 期間 Model
+"""
+from datetime import datetime, date
+from typing import Optional, List, TYPE_CHECKING
+
+from sqlalchemy import String, DateTime, Date
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.core.database import Base
+
+if TYPE_CHECKING:
+    from app.models.kpi_sheet import KPISheet
+
+
+class KPIPeriod(Base):
+    """KPI 期間"""
+
+    __tablename__ = "KPI_D_periods"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    code: Mapped[str] = mapped_column(String(20), unique=True, nullable=False)  # 例: 2024H1
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    start_date: Mapped[date] = mapped_column(Date, nullable=False)
+    end_date: Mapped[date] = mapped_column(Date, nullable=False)
+    setting_start: Mapped[date] = mapped_column(Date, nullable=False)
+    setting_end: Mapped[date] = mapped_column(Date, nullable=False)
+    self_eval_start: Mapped[Optional[date]] = mapped_column(Date)
+    self_eval_end: Mapped[Optional[date]] = mapped_column(Date)
+    manager_eval_start: Mapped[Optional[date]] = mapped_column(Date)
+    manager_eval_end: Mapped[Optional[date]] = mapped_column(Date)
+    status: Mapped[str] = mapped_column(String(20), default="draft")
+    # draft, setting, approved, self_eval, manager_eval, completed
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+    updated_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    # Relationships
+    kpi_sheets: Mapped[List["KPISheet"]] = relationship("KPISheet", back_populates="period")
+
+    @property
+    def is_setting_period(self) -> bool:
+        """是否在設定期間"""
+        today = date.today()
+        return self.setting_start <= today <= self.setting_end
+
+    @property
+    def is_self_eval_period(self) -> bool:
+        """是否在自評期間"""
+        if not self.self_eval_start or not self.self_eval_end:
+            return False
+        today = date.today()
+        return self.self_eval_start <= today <= self.self_eval_end
+
+    @property
+    def is_manager_eval_period(self) -> bool:
+        """是否在主管評核期間"""
+        if not self.manager_eval_start or not self.manager_eval_end:
+            return False
+        today = date.today()
+        return self.manager_eval_start <= today <= self.manager_eval_end
+
+    def __repr__(self) -> str:
+        return f"<KPIPeriod {self.code}: {self.name}>"