feat: add initial project structure with logging and watchdog service

Implement basic watchdog service for Linux systemd with:
- Configuration loading
- Logging system with database support
- WebSocket log broadcasting
- TCP server for agent communication
- Project setup with Go modules

postLog/logBroadcaster.go

@@ -0,0 +1,96 @@
+package postLog
+
+import (
+	"sync"
+)
+
+type LogMessage struct {
+	Level     int    `json:"level"`
+	Content   string `json:"content"`
+	Timestamp string `json:"timestamp"`
+}
+
+type Client struct {
+	ID       string
+	Messages chan LogMessage
+}
+
+type LogBroadcaster struct {
+	mu       sync.RWMutex
+	clients  map[string]chan LogMessage
+	history  []LogMessage
+	historyM sync.RWMutex
+}
+
+var broadcaster *LogBroadcaster
+
+func InitLogBroadcaster() {
+	broadcaster = &LogBroadcaster{
+		clients: make(map[string]chan LogMessage),
+		history: make([]LogMessage, 0),
+	}
+}
+
+func GetLogBroadcaster() *LogBroadcaster {
+	return broadcaster
+}
+
+func (lb *LogBroadcaster) AddClient(id string) chan LogMessage {
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	ch := make(chan LogMessage, 100)
+	lb.clients[id] = ch
+	return ch
+}
+
+func (lb *LogBroadcaster) RemoveClient(id string) {
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	if ch, exists := lb.clients[id]; exists {
+		close(ch)
+		delete(lb.clients, id)
+	}
+}
+
+func (lb *LogBroadcaster) Broadcast(msg LogMessage) {
+	lb.mu.RLock()
+	defer lb.mu.RUnlock()
+
+	for _, ch := range lb.clients {
+		select {
+		case ch <- msg:
+		default:
+		}
+	}
+}
+
+func (lb *LogBroadcaster) GetHistory() []LogMessage {
+	lb.historyM.RLock()
+	defer lb.historyM.RUnlock()
+
+	result := make([]LogMessage, len(lb.history))
+	copy(result, lb.history)
+	return result
+}
+
+func (lb *LogBroadcaster) AddToHistory(msg LogMessage) {
+	lb.historyM.Lock()
+	defer lb.historyM.Unlock()
+
+	lb.history = append(lb.history, msg)
+	if len(lb.history) > 100 {
+		lb.history = lb.history[1:]
+	}
+}
+
+func (lb *LogBroadcaster) SendHistory(clientCh chan LogMessage) {
+	history := lb.GetHistory()
+	for _, msg := range history {
+		select {
+		case clientCh <- msg:
+		default:
+		}
+	}
+}