feat: enhance Worker service with job tracking capabilities

- Add Priority field to Job struct for future job prioritization
- Add HasActiveScans() method to check if any scans are currently running
- Add GetActiveJobCount() method to count running and pending jobs
- Remove unused JobTypeSync constant

These changes enable more accurate health check reporting and prepare
for future job priority queue implementation.

internal/services/worker.go

@@ -38,7 +38,6 @@ const (
 	JobTypeThumbnails    JobType = "thumbnails"
 	JobTypeBackup        JobType = "backup"
 	JobTypeAnalytics     JobType = "analytics"
-	JobTypeSync          JobType = "sync"
 )
 
 var WorkerInstance *Worker
@@ -55,6 +54,7 @@ type Job struct {
 	ID               string
 	Type             JobType
 	UserID           string
+	Priority         int
 	Params           map[string]interface{}
 	Status           JobStatus
 	CreatedAt        time.Time
@@ -94,6 +94,29 @@ type Worker struct {
 	shuttingDown atomic.Bool
 }
 
+func (w *Worker) HasActiveScans() bool {
+	w.mu.RLock()
+	defer w.mu.RUnlock()
+
+	for _, result := range w.results {
+		if result.Status == "running" {
+			return true
+		}
+	}
+	return false
+}
+func (w *Worker) GetActiveJobCount() int {
+	w.mu.RLock()
+	defer w.mu.RUnlock()
+
+	count := 0
+	for _, result := range w.results {
+		if result.Status == "running" || result.Status == "pending" {
+			count++
+		}
+	}
+	return count
+}
 func NewWorker(numWorkers int, connManager *wsync.ConnectionManager) *Worker {
 	ctx, cancel := context.WithCancel(context.Background())