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/core/database.py

@@ -0,0 +1,39 @@
+"""
+資料庫連線設定 (MySQL)
+"""
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, declarative_base
+
+from app.core.config import settings
+
+# 建立資料庫引擎 (MySQL)
+engine = create_engine(
+    settings.DATABASE_URL,
+    pool_pre_ping=True,
+    pool_size=10,
+    max_overflow=20,
+    pool_recycle=3600,  # MySQL 連線回收
+)
+
+# 建立 Session 工廠
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# 建立 Base 類別
+Base = declarative_base()
+
+
+def get_db():
+    """
+    取得資料庫 Session
+    用於 FastAPI 依賴注入
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def init_db():
+    """初始化資料庫（建立所有表）"""
+    Base.metadata.create_all(bind=engine)