fix: resolve critical bugs and refactor code structure

P0 Fixes:
- Fix potential panic in factory.go due to unsafe type assertion
- Fix VIP CIDR mask being lost during parsing (was hardcoded to /32)

P1 Fixes:
- Fix go.mod incorrect indirect dependency markers
- Fix receiveLoop blocking issue preventing graceful shutdown

Refactoring:
- Split state.go into state.go, timer.go, priority.go, history.go
- Split monitor.go into monitor.go and manager.go
- Add IncreasePriority() method for complete priority adjustment
- Fix go vet format string warning in test.go

🤖 Generated with [Qoder][https://qoder.com]

internal/health/manager.go

@@ -0,0 +1,74 @@
+package health
+
+import (
+	"sync"
+
+	"github.com/loveuer/go-alived/pkg/logger"
+)
+
+// Manager manages multiple health check monitors.
+type Manager struct {
+	monitors map[string]*Monitor
+	mu       sync.RWMutex
+	log      *logger.Logger
+}
+
+// NewManager creates a new health check Manager.
+func NewManager(log *logger.Logger) *Manager {
+	return &Manager{
+		monitors: make(map[string]*Monitor),
+		log:      log,
+	}
+}
+
+// AddMonitor adds a monitor to the manager.
+func (m *Manager) AddMonitor(monitor *Monitor) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.monitors[monitor.config.Name] = monitor
+}
+
+// GetMonitor retrieves a monitor by name.
+func (m *Manager) GetMonitor(name string) (*Monitor, bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	monitor, ok := m.monitors[name]
+	return monitor, ok
+}
+
+// StartAll starts all registered monitors.
+func (m *Manager) StartAll() {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	for _, monitor := range m.monitors {
+		monitor.Start()
+	}
+
+	m.log.Info("started %d health check monitor(s)", len(m.monitors))
+}
+
+// StopAll stops all registered monitors.
+func (m *Manager) StopAll() {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	for _, monitor := range m.monitors {
+		monitor.Stop()
+	}
+
+	m.log.Info("stopped all health check monitors")
+}
+
+// GetAllStates returns the current state of all monitors.
+func (m *Manager) GetAllStates() map[string]*CheckerState {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	states := make(map[string]*CheckerState)
+	for name, monitor := range m.monitors {
+		states[name] = monitor.GetState()
+	}
+
+	return states
+}