instrument: fix AHD node-tracking/tie-break/live-latch defects and close staged-envelope-curve test gaps

tests/test_theme.cpp

@@ -132,13 +132,18 @@ static void testOverlayAccentSeparatesFromTheWaveformAccent() {
     const KitColor overlay = roleColor(Role::AccentTertiary);
     const KitColor prior = roleColor(Role::AccentSecondary);
     CHECK(contrastRatio(overlay, wave) > contrastRatio(prior, wave));
+    // Pin the MEASURED value, not just the relational improvement: today's pair sits at
+    // ~1.37:1 — BELOW the 3:1 indicator floor every other assertion in this file uses. That
+    // is a known, held deviation (Daniel's palette call, tracked separately) rather than a
+    // silently accepted one; a regression toward the old ~1.12:1 secondary pairing must fail.
+    CHECK(contrastRatio(overlay, wave) >= 1.35);
     // Hue divergence against the waveform: the waveform's green dominates its red, the
     // overlay's red dominates its green — opposite balances, not two shades of one.
     CHECK(wave.g > wave.r);
     CHECK(overlay.r > overlay.g);
     const int delta = std::abs(int(wave.r) - int(overlay.r)) +
                       std::abs(int(wave.g) - int(overlay.g)) +
-                      std::abs(int(wave.b) - int(overlay.b)) ;
+                      std::abs(int(wave.b) - int(overlay.b));
     CHECK(delta >= 60);
 }