Complete managed macOS platform bring-up

tests/test_external_pcm.cpp

@@ -219,6 +219,7 @@ static void test_feed_pcm_round_trip(uint16_t port) {
         CHECK(energy > 0);
 
         vc_stream_stop(clientA, a_sid);
+        CHECK(vc_set_pcm_sink(clientB, nullptr, nullptr) == VC_OK);
     }
 
 cleanup_rt:
@@ -290,6 +291,7 @@ static void test_feed_pcm_stereo(uint16_t port) {
         CHECK(R < L || L == 0);  // L >= R (loud-L / quiet-R)
 
         vc_stream_stop(clientA, a_sid);
+        CHECK(vc_set_pcm_sink(clientB, nullptr, nullptr) == VC_OK);
     }
 
 cleanup_st:

tests/test_frame_ms_reframe.cpp

@@ -225,6 +225,7 @@ static void run_case(uint16_t port, vc_client* admin, EventStore& evAdmin,
         CHECK(sink.last_sample_rate == 48000);
 
         vc_stream_stop(clientA, a_sid);
+        CHECK(vc_set_pcm_sink(clientB, nullptr, nullptr) == VC_OK);
     }
 
 cleanup: