fix: add sleep before poller data insert to prevent race condition in tests

The poller's Start() calls GetMaxTransmissionID() to initialize its cursor.
When the test goroutine inserts data between go poller.Start() and the
actual GetMaxTransmissionID() call, the poller's cursor skips past the
test data and never broadcasts it, causing a timeout.

Adding a 100ms sleep after go poller.Start() ensures the poller has
initialized its cursors before the test inserts new data.

cmd/server/parity_test.go

@@ -424,6 +424,11 @@ func TestParityWSMultiObserverGolden(t *testing.T) {
 	go poller.Start()
 	defer poller.Stop()
 
+	// Wait for poller to initialize its lastID/lastObsID cursors before
+	// inserting new data; otherwise the poller may snapshot a lastID that
+	// already includes the test data and never broadcast it.
+	time.Sleep(100 * time.Millisecond)
+
 	now := time.Now().UTC().Format(time.RFC3339)
 	if _, err := db.conn.Exec(`INSERT INTO transmissions (raw_hex, hash, first_seen, route_type, payload_type, decoded_json)
 		VALUES ('BEEF', 'goldenstarburst237', ?, 1, 4, '{"pubKey":"aabbccdd11223344","type":"ADVERT"}')`, now); err != nil {

cmd/server/websocket_test.go

@@ -278,6 +278,11 @@ func TestPollerBroadcastsMultipleObservations(t *testing.T) {
 	go poller.Start()
 	defer poller.Stop()
 
+	// Wait for poller to initialize its lastID/lastObsID cursors before
+	// inserting new data; otherwise the poller may snapshot a lastID that
+	// already includes the test data and never broadcast it.
+	time.Sleep(100 * time.Millisecond)
+
 	now := time.Now().UTC().Format(time.RFC3339)
 	if _, err := db.conn.Exec(`INSERT INTO transmissions (raw_hex, hash, first_seen, route_type, payload_type, decoded_json)
 		VALUES ('FACE', 'starbursthash237a', ?, 1, 4, '{"pubKey":"aabbccdd11223344","type":"ADVERT"}')`, now); err != nil {