fix: replace context.Done() with Wait() in backend tests (#75)

Replace ctx.Done() with proper Wait() method calls in proxy and transparent
backend tests to ensure proper cleanup and synchronization.

Author: hrntknr

pkg/backend/proxy_test.go

@@ -85,7 +85,7 @@ func TestProxyBackendRun(t *testing.T) {
 
 	checkCh := make(chan struct{})
 	go func() {
-		<-ctx.Done()
+		pb.Wait()
 		close(checkCh)
 	}()
 

pkg/backend/transparent_test.go

@@ -114,7 +114,7 @@ func TestTransparentBackendRun(t *testing.T) {
 
 	checkCh := make(chan struct{})
 	go func() {
-		<-ctx.Done()
+		be.Wait()
 		close(checkCh)
 	}()