Refactor: Java-Klassen aus Services entfernt + kritische Bugs gefixt

- AuthService, SystemInfo, IdentitiesManager Klassen → Modul-Funktionen
- grp.getall() → grp.getgrall() (Bug: Methode existierte nie)
- open('/proc/loadavg') ohne context manager gefixt (File-Handle-Leak)
- rx_packets/tx_packets null-check im Frontend (toLocaleString auf undefined)
- PoolCard onClick: /pools/{name} → /zfs (Route existierte nicht, löste Seitenreload aus)
- Alle Router-Imports auf Modul-Aliase umgestellt

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/services/auth.py

@@ -12,78 +12,51 @@ from jose import JWTError, jwt
 
 logger = logging.getLogger(__name__)
 
-# JWT Configuration
 SECRET_KEY = os.environ.get("ZFS_SECRET_KEY", "your-secret-key-change-in-production")
 ALGORITHM = "HS256"
 ACCESS_TOKEN_EXPIRE_HOURS = 8
 
-# Try to import PAM for system authentication
 try:
     import pam
     PAM_AVAILABLE = True
+    logger.info("Using PAM authentication (Linux system users)")
 except ImportError:
     PAM_AVAILABLE = False
     logger.warning("python-pam not installed, PAM authentication unavailable")
 
 
-class AuthService:
-    def __init__(self):
-        """Initialize auth service with PAM (Linux system users)"""
-        if PAM_AVAILABLE:
-            logger.info("Using PAM authentication (Linux system users)")
-        else:
-            logger.error("PAM not available - install python-pam for authentication")
-
-    def authenticate_user(self, username: str, password: str) -> Optional[dict]:
-        """
-        Authenticate user via PAM (Linux system users like 'pi', 'root')
-        Returns user data if valid, None otherwise
-        """
-        if not PAM_AVAILABLE:
-            logger.error("PAM not available")
-            return None
-
-        try:
-            p = pam.pam()
-            if p.authenticate(username, password):
-                logger.info(f"User {username} authenticated via PAM")
-                return {
-                    "username": username,
-                    "source": "pam"
-                }
-            else:
-                logger.warning(f"PAM authentication failed for user {username}: {p.reason}")
-                return None
-        except Exception as e:
-            logger.error(f"PAM authentication error: {e}")
-            return None
-
-    def create_access_token(self, username: str, expires_delta: Optional[timedelta] = None) -> str:
-        """Create JWT access token"""
-        if expires_delta is None:
-            expires_delta = timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS)
-
-        expire = datetime.utcnow() + expires_delta
-        to_encode = {"sub": username, "exp": expire}
-
-        try:
-            encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
-            return encoded_jwt
-        except Exception as e:
-            logger.error(f"Failed to create token: {e}")
-            raise
-
-    def verify_token(self, token: str) -> Optional[str]:
-        """Verify JWT token and return username"""
-        try:
-            payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
-            username: str = payload.get("sub")
-            if username is None:
-                return None
-            return username
-        except JWTError:
-            return None
+def authenticate_user(username: str, password: str) -> Optional[dict]:
+    if not PAM_AVAILABLE:
+        logger.error("PAM not available")
+        return None
+    try:
+        p = pam.pam()
+        if p.authenticate(username, password):
+            logger.info(f"User {username} authenticated via PAM")
+            return {"username": username, "source": "pam"}
+        logger.warning(f"PAM authentication failed for user {username}: {p.reason}")
+        return None
+    except Exception as e:
+        logger.error(f"PAM authentication error: {e}")
+        return None
 
 
-# Global instance
-auth_service = AuthService()
+def create_access_token(username: str, expires_delta: Optional[timedelta] = None) -> str:
+    if expires_delta is None:
+        expires_delta = timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS)
+    expire = datetime.utcnow() + expires_delta
+    to_encode = {"sub": username, "exp": expire}
+    try:
+        return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+    except Exception as e:
+        logger.error(f"Failed to create token: {e}")
+        raise
+
+
+def verify_token(token: str) -> Optional[str]:
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username: str = payload.get("sub")
+        return username if username else None
+    except JWTError:
+        return None