Loop-crossfade-ux review fixes: parked-drag no longer fakes LOOP OFF, waveform label contrast fixed, hover memoizes its bank read

Also corrects the cap-area, em-dash, glyph-overhang and heuristic-comment findings noted in review.

tests/test_loop_marks.cpp

@@ -176,6 +176,21 @@ static void testEditingTheStartMarkerWhileOffLeavesTheEnableAndCrossfadeAlone()
     CHECK(w.start == 512);
 }
 
+// Dragging the START marker while parked (never set) must not turn "DRAG TO SET LOOP" into
+// "LOOP OFF" — the ordinary gesture that exposed the bug, distinct from the retained-span case
+// above.
+static void testEditingTheStartMarkerWhileParkedStaysParked() {
+    LoopMarks m = resolveLoopMarks(StoredLoop{}, kFrames);
+    CHECK(m.parked && !m.hasLoop);
+    m.start = 512;
+    const LoopMarks after = writeThenRead(m);
+    CHECK(!after.hasLoop);
+    CHECK(after.parked);
+    const LoopBounds d = defaultLoopBounds(kFrames);
+    CHECK(after.loopStart == d.start && after.loopEnd == d.end);
+    CHECK(after.start == 512);
+}
+
 static void testANegativeCrossfadeNeverReachesTheStore() {
     LoopMarks m = resolveLoopMarks(storedSpan(true, 4000, 6000, 0), kFrames);
     m.crossfade = -1;
@@ -197,6 +212,7 @@ int main() {
     testDraggingALoopMarkWhileOffTurnsItOn();
 
     testEditingTheStartMarkerWhileOffLeavesTheEnableAndCrossfadeAlone();
+    testEditingTheStartMarkerWhileParkedStaysParked();
     testANegativeCrossfadeNeverReachesTheStore();
 
     if (g_fail == 0) {