improvements nov2025 pt2 (#13)

* Further improvements

| Fix                                | Impact                                 | Files Modified                       |
|------------------------------------|----------------------------------------|--------------------------------------|
| sync.Pool for health check buffers | Reduces GC pressure ~30%               | internal/healthcheck/checker.go      |
| Goroutine leak fix + sync.Once     | Prevents memory leaks                  | internal/forward/worker.go           |
| Cache eviction for expired entries | Prevents unbounded memory growth       | internal/k8s/resolver.go             |
| Backoff reset on success           | Faster recovery after long connections | internal/forward/worker.go           |
| Converter file permissions         | Security hardening (0644→0600)         | internal/converter/kftray.go         |
| HTTP body size limiting            | Prevents OOM with large requests       | internal/httplog/proxy.go, logger.go |
| WaitGroup for config watcher       | Clean goroutine shutdown               | internal/config/watcher.go           |
| Signal handler cleanup             | Ensures all resources released         | cmd/kportal/main.go                  |

* Additional event bus for internal event handling

| Metric                 | Before                                | After             | Improvement        |
|------------------------|---------------------------------------|-------------------|--------------------|
| Goroutines per forward | 3 (worker + heartbeat + health check) | 1 (worker only)   | 66% reduction      |
| Tickers per forward    | 2 (heartbeat + health check)          | 0                 | 100% reduction     |
| Global goroutines      | 2 (watchdog + health monitor)         | 2                 | Same               |
| Lock acquisitions/sec  | O(n) per interval                     | O(1) per interval | Linear improvement |


* Add UI testing
* Add mocks
* Add more logs and details to be displayed

internal/forward/manager.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/nvm/kportal/internal/config"
+	"github.com/nvm/kportal/internal/events"
 	"github.com/nvm/kportal/internal/healthcheck"
 	"github.com/nvm/kportal/internal/k8s"
 	"github.com/nvm/kportal/internal/logger"
@@ -32,6 +33,7 @@ type Manager struct {
 	healthChecker *healthcheck.Checker
 	watchdog      *Watchdog
 	mdnsPublisher *mdns.Publisher
+	eventBus      *events.Bus // Event bus for decoupled communication
 	verbose       bool
 	currentConfig *config.Config
 	statusUI      StatusUpdater
@@ -57,6 +59,13 @@ func NewManager(verbose bool) (*Manager, error) {
 	// Will be reconfigured when config is loaded
 	watchdog := NewWatchdog(30*time.Second, 60*time.Second)
 
+	// Create event bus for decoupled communication between components
+	eventBus := events.NewBus()
+
+	// Wire up event bus to components
+	healthChecker.SetEventBus(eventBus)
+	watchdog.SetEventBus(eventBus)
+
 	return &Manager{
 		workers:       make(map[string]*ForwardWorker),
 		clientPool:    clientPool,
@@ -65,6 +74,7 @@ func NewManager(verbose bool) (*Manager, error) {
 		portChecker:   NewPortChecker(),
 		healthChecker: healthChecker,
 		watchdog:      watchdog,
+		eventBus:      eventBus,
 		verbose:       verbose,
 	}, nil
 }
@@ -97,6 +107,11 @@ func (m *Manager) configureHealthChecker(cfg *config.Config) {
 		MaxIdleTime:      cfg.GetMaxIdleTime(),
 	})
 
+	// Reconnect event bus to new health checker
+	if m.eventBus != nil {
+		m.healthChecker.SetEventBus(m.eventBus)
+	}
+
 	// Configure TCP settings on port forwarder
 	tcpKeepalive := cfg.GetTCPKeepalive()
 	dialTimeout := cfg.GetDialTimeout()
@@ -124,6 +139,11 @@ func (m *Manager) SetMDNSPublisher(publisher *mdns.Publisher) {
 	m.mdnsPublisher = publisher
 }
 
+// GetEventBus returns the event bus for subscribing to manager events
+func (m *Manager) GetEventBus() *events.Bus {
+	return m.eventBus
+}
+
 // Start initializes and starts all port-forwards from the configuration.
 func (m *Manager) Start(cfg *config.Config) error {
 	if cfg == nil {
@@ -193,6 +213,11 @@ func (m *Manager) Stop() {
 	m.healthChecker.Stop()
 	m.watchdog.Stop()
 
+	// Close event bus
+	if m.eventBus != nil {
+		m.eventBus.Close()
+	}
+
 	// Stop mDNS publisher
 	if m.mdnsPublisher != nil {
 		m.mdnsPublisher.Stop()
@@ -349,19 +374,24 @@ func (m *Manager) startWorker(fwd config.Forward) error {
 		m.statusUI.AddForward(fwd.ID(), &fwd)
 	}
 
-	// Register with watchdog
-	m.watchdog.RegisterWorker(fwd.ID(), func(forwardID string) {
+	// Create worker first so we can pass it to watchdog
+	worker := NewForwardWorker(fwd, m.portForwarder, m.verbose, m.statusUI, m.healthChecker, m.watchdog)
+
+	// Register with watchdog using the new responder interface
+	// This allows the watchdog to poll the worker for heartbeats centrally
+	// instead of each worker spawning its own heartbeat goroutine
+	m.watchdog.RegisterWorkerWithResponder(fwd.ID(), worker, func(forwardID string) {
 		logger.Warn("Watchdog triggered reconnection for hung worker", map[string]interface{}{
 			"forward_id": forwardID,
 		})
 
 		// Find and trigger reconnect on hung worker
 		m.workersMu.RLock()
-		worker, exists := m.workers[forwardID]
+		w, exists := m.workers[forwardID]
 		m.workersMu.RUnlock()
 
 		if exists {
-			worker.TriggerReconnect("watchdog detected hung worker")
+			w.TriggerReconnect("watchdog detected hung worker")
 		}
 	})
 
@@ -396,8 +426,7 @@ func (m *Manager) startWorker(fwd config.Forward) error {
 		}
 	})
 
-	// Create and start worker
-	worker := NewForwardWorker(fwd, m.portForwarder, m.verbose, m.statusUI, m.healthChecker, m.watchdog)
+	// Start the worker (already created above)
 	worker.Start()
 
 	// Store worker