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) {

tests/test_sample_chrome.cpp

@@ -157,8 +157,9 @@ static void testHoldCellIsReservedAndFollowsTheVelocityCellGrammar() {
 // the agreed remedy if it cannot is to narrow the enable's segments, never to move the floor.
 static void testTheControlRunLeavesTheTitleReadableAtTheEditorFloor() {
     const ChromeRects r = chromeRects(chromeBand(), kKnob);
-    // "ReaSampler 9000" (15 chars) plus a bracketed 20-char capture name, at the toolbar font's
-    // generous ~7 px/char estimate: 38 * 7.
+    // "ReaSampler 9000" (15 chars) plus a bracketed 20-char capture name, at an assumed 7 px/char
+    // for the toolbar font: 38 * 7. A HEURISTIC, not a measured Segoe UI metric — no font-metric
+    // measurement backs this number; it gates a phase-wide acceptance criterion regardless.
     constexpr int kTitleTextFloorPx = 266;
     CHECK(r.title.width >= kTitleTextFloorPx);
     // Nothing in the run reaches into the title's slot.

tests/test_theme.cpp

@@ -269,6 +269,25 @@ static void testCardNameScrimClearsBodyFloorOnItsWorstBackground() {
           < textFloor(TextClass::Body));
 }
 
+// The waveform band's state caption and its four mark labels (editor_paint_waveform.cpp) draw
+// text/dim (the caption, the non-promoted labels) and text/primary (the promoted label) — both
+// Font::Micro, both body class — over a bg/base scrim at kWaveformLabelScrimAlpha, itself drawn
+// over whatever drawEnvelope left in that rect. Unlike the card name strip, the worst case here
+// is text/DIM, not text/primary, so the alpha is higher than kCardNameScrimAlpha's — pin both
+// roles against the worst background (a full-scale envelope peak, accent/primary) and pin the
+// defect the scrim exists to close.
+static void testWaveformLabelScrimClearsBodyFloorOnItsWorstBackground() {
+    const KitColor scrim = roleColor(Role::BgBase);
+    const KitColor onFill = compositeOver(scrim, roleColor(Role::AccentPrimary),
+                                          kWaveformLabelScrimAlpha);
+    CHECK(contrastRatio(roleColor(Role::TextDim), onFill) >= textFloor(TextClass::Body));
+    CHECK(contrastRatio(roleColor(Role::TextPrimary), onFill) >= textFloor(TextClass::Body));
+    // Without the scrim, text/dim on the bare accent-lime fill is UNDER floor (~1.58:1) — pins
+    // the defect the scrim exists to close, so a future removal of the scrim fails this first.
+    CHECK(contrastRatio(roleColor(Role::TextDim), roleColor(Role::AccentPrimary))
+          < textFloor(TextClass::Body));
+}
+
 // --- Single point of change (structural guarantee) ----------------------------
 //
 // roleColor is the ONLY color source; there is no other public accessor that yields a
@@ -366,6 +385,7 @@ int main() {
     testTextOnPastelFillClearsBodyFloor();
     testTextOnHoverSurfaceClearsFloor();
     testCardNameScrimClearsBodyFloorOnItsWorstBackground();
+    testWaveformLabelScrimClearsBodyFloorOnItsWorstBackground();
     testCurveTraceOnHoverSurfaceClearsFloor();
     testSecondaryTertiaryAreDistinguishable();
     testOverlayTraceClearsIndicatorFloorOnTheWaveform();