fix: 修正系统监控API返回数据结构

匹配JavaScript期待的数据结构：
- system.uptime（系统运行时间）
- system.boot_time（启动时间）
- system.process_count（进程数）
- cpu.count/cpu.logical（CPU核心数）
- disk.free_gb（磁盘剩余空间）
- network.sent_mb/recv_mb（累计流量）
- network.sent_speed/recv_speed（实时网速）

确保前端能正确显示所有系统资源信息

routes_system.py

@@ -6,7 +6,7 @@
 import os
 import subprocess
 import time
-from flask import jsonify
+from datetime import datetime
 from utils import log_message, get_cpu_temperatures, load_alert_config
 
 try:
@@ -82,10 +82,15 @@ def register_system_routes(app):
             
             return jsonify({
                 'available': True,
+                'system': {
+                    'uptime': uptime_str,
+                    'boot_time': datetime.fromtimestamp(boot_time).strftime('%Y-%m-%d %H:%M:%S'),
+                    'process_count': process_count
+                },
                 'cpu': {
                     'percent': cpu_percent,
-                    'count_physical': cpu_count,
-                    'count_logical': cpu_count_logical,
+                    'count': cpu_count,
+                    'logical': cpu_count_logical,
                     'temp_package_0': cpu_temps.get('package_0'),
                     'temp_package_1': cpu_temps.get('package_1')
                 },
@@ -98,14 +103,15 @@ def register_system_routes(app):
                 'disk': {
                     'total_gb': disk_total_gb,
                     'used_gb': disk_used_gb,
+                    'free_gb': round(disk.free / (1024**3), 2),
                     'percent': disk_percent
                 },
                 'network': {
-                    'upload_speed_kb': round(upload_speed, 2),
-                    'download_speed_kb': round(download_speed, 2)
-                },
-                'process_count': process_count,
-                'uptime': uptime_str
+                    'sent_mb': round(net.bytes_sent / (1024**2), 2),
+                    'recv_mb': round(net.bytes_recv / (1024**2), 2),
+                    'sent_speed': round(upload_speed, 2),
+                    'recv_speed': round(download_speed, 2)
+                }
             })
         except Exception as e:
             return jsonify({'error': str(e)}), 500