feat: Implement server and client metrics collection and monitoring

- Added a new PHP script for collecting server metrics every 30 seconds.
- Created a ServerMonitoring class to handle metrics collection for CPU, RAM, Disk, and Network.
- Introduced database tables for storing server and client metrics.
- Updated server view template to display real-time metrics using Chart.js.
- Added translations for monitoring UI elements.
- Created a new monitoring template for detailed server metrics visualization.
- Implemented client speed tracking and display in the monitoring UI.

migrations/009_add_server_metrics.sql

@@ -0,0 +1,31 @@
+-- Add server metrics tables
+-- This migration adds functionality to store and display server monitoring data
+
+-- Server metrics (CPU, RAM, Disk, Network)
+CREATE TABLE IF NOT EXISTS server_metrics (
+  id BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  server_id INT UNSIGNED NOT NULL,
+  cpu_percent DECIMAL(5,2) NULL COMMENT 'CPU usage percentage',
+  ram_used_mb INT UNSIGNED NULL COMMENT 'RAM used in MB',
+  ram_total_mb INT UNSIGNED NULL COMMENT 'Total RAM in MB',
+  disk_used_gb DECIMAL(10,2) NULL COMMENT 'Disk used in GB',
+  disk_total_gb DECIMAL(10,2) NULL COMMENT 'Total disk in GB',
+  network_rx_mbps DECIMAL(10,2) NULL COMMENT 'Network receive speed in Mbps',
+  network_tx_mbps DECIMAL(10,2) NULL COMMENT 'Network transmit speed in Mbps',
+  collected_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_server_time (server_id, collected_at),
+  FOREIGN KEY (server_id) REFERENCES vpn_servers(id) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- Client traffic metrics (speed tracking)
+CREATE TABLE IF NOT EXISTS client_metrics (
+  id BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  client_id INT UNSIGNED NOT NULL,
+  bytes_sent BIGINT UNSIGNED DEFAULT 0 COMMENT 'Bytes sent at this moment',
+  bytes_received BIGINT UNSIGNED DEFAULT 0 COMMENT 'Bytes received at this moment',
+  speed_up_kbps DECIMAL(10,2) NULL COMMENT 'Upload speed in Kbps',
+  speed_down_kbps DECIMAL(10,2) NULL COMMENT 'Download speed in Kbps',
+  collected_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_client_time (client_id, collected_at),
+  FOREIGN KEY (client_id) REFERENCES vpn_clients(id) ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

migrations/010_add_monitoring_translations.sql

@@ -0,0 +1,92 @@
+-- Add translations for monitoring UI elements
+
+INSERT INTO translations (translation_key, language_code, translation_value) VALUES 
+-- Speed
+('common.speed', 'en', 'Speed'),
+('common.speed', 'ru', 'Скорость'),
+('common.speed', 'es', 'Velocidad'),
+('common.speed', 'de', 'Geschwindigkeit'),
+('common.speed', 'fr', 'Vitesse'),
+('common.speed', 'zh', '速度'),
+
+-- Metrics
+('common.metrics', 'en', 'Metrics'),
+('common.metrics', 'ru', 'Метрики'),
+('common.metrics', 'es', 'Métricas'),
+('common.metrics', 'de', 'Metriken'),
+('common.metrics', 'fr', 'Métriques'),
+('common.metrics', 'zh', '指标'),
+
+-- Server Info
+('servers.server_info', 'en', 'Server Info'),
+('servers.server_info', 'ru', 'Информация о сервере'),
+('servers.server_info', 'es', 'Información del servidor'),
+('servers.server_info', 'de', 'Serverinformationen'),
+('servers.server_info', 'fr', 'Informations sur le serveur'),
+('servers.server_info', 'zh', '服务器信息'),
+
+-- Status
+('common.status', 'en', 'Status'),
+('common.status', 'ru', 'Статус'),
+('common.status', 'es', 'Estado'),
+('common.status', 'de', 'Status'),
+('common.status', 'fr', 'Statut'),
+('common.status', 'zh', '状态'),
+
+-- Client Configuration
+('clients.configuration', 'en', 'Client Configuration'),
+('clients.configuration', 'ru', 'Конфигурация клиента'),
+('clients.configuration', 'es', 'Configuración del cliente'),
+('clients.configuration', 'de', 'Client-Konfiguration'),
+('clients.configuration', 'fr', 'Configuration du client'),
+('clients.configuration', 'zh', '客户端配置'),
+
+-- Traffic Statistics
+('clients.traffic_stats', 'en', 'Traffic Statistics'),
+('clients.traffic_stats', 'ru', 'Статистика трафика'),
+('clients.traffic_stats', 'es', 'Estadísticas de tráfico'),
+('clients.traffic_stats', 'de', 'Traffic-Statistiken'),
+('clients.traffic_stats', 'fr', 'Statistiques de trafic'),
+('clients.traffic_stats', 'zh', '流量统计'),
+
+-- Uploaded
+('common.uploaded', 'en', 'Uploaded'),
+('common.uploaded', 'ru', 'Отправлено'),
+('common.uploaded', 'es', 'Subido'),
+('common.uploaded', 'de', 'Hochgeladen'),
+('common.uploaded', 'fr', 'Envoyé'),
+('common.uploaded', 'zh', '上传'),
+
+-- Downloaded
+('common.downloaded', 'en', 'Downloaded'),
+('common.downloaded', 'ru', 'Получено'),
+('common.downloaded', 'es', 'Descargado'),
+('common.downloaded', 'de', 'Heruntergeladen'),
+('common.downloaded', 'fr', 'Reçu'),
+('common.downloaded', 'zh', '下载'),
+
+-- Total
+('common.total', 'en', 'Total'),
+('common.total', 'ru', 'Всего'),
+('common.total', 'es', 'Total'),
+('common.total', 'de', 'Gesamt'),
+('common.total', 'fr', 'Total'),
+('common.total', 'zh', '总计'),
+
+-- Created
+('common.created', 'en', 'Created'),
+('common.created', 'ru', 'Создан'),
+('common.created', 'es', 'Creado'),
+('common.created', 'de', 'Erstellt'),
+('common.created', 'fr', 'Créé'),
+('common.created', 'zh', '创建时间'),
+
+-- IP Address
+('common.ip_address', 'en', 'IP Address'),
+('common.ip_address', 'ru', 'IP-адрес'),
+('common.ip_address', 'es', 'Dirección IP'),
+('common.ip_address', 'de', 'IP-Adresse'),
+('common.ip_address', 'fr', 'Adresse IP'),
+('common.ip_address', 'zh', 'IP地址')
+
+ON DUPLICATE KEY UPDATE translation_value=VALUES(translation_value);