feat(api): implement API key generation and management functionality

Signed-off-by: luckfox-eng29 <eng29@luckfox.com>

config.go

@@ -3,6 +3,8 @@ package kvm
 import (
 	"bufio"
 	"bytes"
+	"crypto/rand"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -497,6 +499,14 @@ func SaveConfig() error {
 	return nil
 }
 
+func generateAPIKey() (string, error) {
+	bytes := make([]byte, 32)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(bytes), nil
+}
+
 func ensureConfigLoaded() {
 	if config == nil {
 		LoadConfig()