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/security.py

@@ -0,0 +1,83 @@
+"""
+安全模組：JWT 認證與密碼雜湊
+"""
+from datetime import datetime, timedelta
+from typing import Optional
+
+from jose import JWTError, jwt
+from passlib.context import CryptContext
+
+from app.core.config import settings
+
+# 密碼雜湊上下文
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """驗證密碼"""
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    """產生密碼雜湊"""
+    return pwd_context.hash(password)
+
+
+def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
+    """
+    建立 Access Token
+
+    Args:
+        data: Token 內容 (通常包含 sub: user_id)
+        expires_delta: 過期時間
+
+    Returns:
+        JWT Token 字串
+    """
+    to_encode = data.copy()
+
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+
+    to_encode.update({"exp": expire, "type": "access"})
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+    return encoded_jwt
+
+
+def create_refresh_token(data: dict) -> str:
+    """
+    建立 Refresh Token
+
+    Args:
+        data: Token 內容
+
+    Returns:
+        JWT Token 字串
+    """
+    to_encode = data.copy()
+    expire = datetime.utcnow() + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)
+
+    to_encode.update({"exp": expire, "type": "refresh"})
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+    return encoded_jwt
+
+
+def decode_token(token: str) -> Optional[dict]:
+    """
+    解碼 Token
+
+    Args:
+        token: JWT Token 字串
+
+    Returns:
+        Token 內容或 None (解碼失敗)
+    """
+    try:
+        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
+        return payload
+    except JWTError:
+        return None