Say what a relative nudge key costs when two arrive together

The latency keys read the tracker's current offset and add to it. Two
presses landing in the same round of the console's loop both read the
same value, and the control queue keeps only the newer SetTempoOptions,
so one five-millisecond step is lost. Key repeat is 33 ms apart and the
line printed after each press shows the same number twice, so it takes a
deliberate double-tap to hit and is obvious when you do — but the next
thing to wire a control to post() should know the shape, because a UI
slider sends an absolute value and does not have the question.

Author: Fohdeesha

src/cli/main.cpp

@@ -1259,6 +1259,12 @@ int runTrackDevice(const TrackArgs& args, const takt4::model::ModelWeights& weig
             break;
         case '[':
         case ']': {
+            // A relative nudge reads what is there and adds to it, so two presses landing
+            // in the same 1 ms round would both read the same value and the queue would
+            // keep only the second — one step of five milliseconds lost, and visible in
+            // the line below, which prints the same number twice. Key repeat is 33 ms
+            // apart, so it takes a deliberate double-tap. A UI with a real slider sends an
+            // absolute value and does not have the question.
             takt4::tracking::TempoTracker::Options live = engine->tempoOptions();
             live.latencyOffsetSeconds += key == '[' ? -0.005 : 0.005;
             (void)engine->post(Command::setTempoOptions(live));