fix: S12 R2 — marker-drag sets selectedZone_, ADSR rate-resolve, gateAdsr doc

Marker drag now sets selectedZone_ so single-capture controls stay reachable. Lifted/default ADSR rescales nominal 44100-Hz frame counts by sampleRate/44100 via adsrNeedsRateResolve; v4-authored zones skip rescale. gateAdsr documented vestigial.

tests/test_sample_map.cpp

@@ -1194,6 +1194,84 @@ static void testV3BlobLiftsAdsrToNominalDefaults() {
     CHECK(a.decayFrames   == kTier0NominalDecayFrames);     // 0
     CHECK(a.sustainLevel  == kTier0NominalSustainLevel);    // 1.0
     CHECK(a.releaseFrames == kTier0NominalReleaseFrames);   // 2646 (0.060 s at 44100)
+    // The lifted zone must be flagged for rate-resolve so buildZonedKeymap rescales at the live rate.
+    CHECK(back.zones[0].adsrNeedsRateResolve == true);
+}
+
+// A v4 blob (explicit A/D/S/R tail) must NOT set adsrNeedsRateResolve — those values
+// were authored at the DAW's rate and must not be rescaled again at keymap build time.
+static void testV4BlobClearsAdsrNeedsRateResolve() {
+    PerformanceMap m;
+    PerformanceZone z = zone("pad", 0, 127);
+    z.play.adsr.attackFrames  = 441;
+    z.play.adsr.releaseFrames = 8820;
+    m.zones.push_back(z);
+    // A round-trip through serialize/deserialize writes a v4 payload (current version).
+    const PerformanceMap back = deserializePerformance(serializePerformance(m));
+    CHECK(back.zones.size() == 1);
+    if (back.zones.size() != 1) return;
+    // v4 tail was explicitly read — adsrNeedsRateResolve must be false.
+    CHECK(back.zones[0].adsrNeedsRateResolve == false);
+}
+
+// buildTier0Keymap at 48k must produce ADSR frame counts equal to tier0Adsr(48000):
+// attack = round(kTier0NominalAttackFrames * 48000 / 44100) = round(143.67) = 144,
+// release = round(kTier0NominalReleaseFrames * 48000 / 44100) = round(2880.0) = 2880.
+// This is the "pre-fix, the Gate voice used tier0Adsr(sampleRate_)" invariant restored
+// for the single-capture fast path at any DAW rate.
+static void testBuildTier0KeymapRescalesAdsrAt48k() {
+    const Keymap km = buildTier0Keymap({0.5f}, 48000, 60, SampleLoop{});
+    CHECK(km.samples.size() == 1);
+    if (km.samples.empty()) return;
+    const AdsrParams& a = km.samples[0].play.adsr;
+    // Rescaled from 44100-nominal at 48000 Hz:
+    CHECK(a.attackFrames  == 144);   // round(132 * 48000.0 / 44100.0)
+    CHECK(a.decayFrames   == 0);     // 0 * factor = 0 (no change)
+    CHECK(a.sustainLevel  == 1.0);   // level, not frames (no rescale)
+    CHECK(a.releaseFrames == 2880);  // round(2646 * 48000.0 / 44100.0)
+}
+
+// buildZonedKeymap at 48k with adsrNeedsRateResolve=true must rescale ADSR to match
+// tier0Adsr(48000), mirroring what Gate voices saw before the per-zone-ADSR fix.
+static void testBuildZonedKeymapRescalesNominalAdsrAt48k() {
+    // Build a zone with nominal 44100-Hz ADSR and the needs-resolve flag (the default).
+    ResolvedZone z;
+    z.lowNote = 0; z.highNote = 127; z.rootNote = 60;
+    z.adsrNeedsRateResolve = true;   // 44100-nominal values, rescale needed
+    z.play.adsr.attackFrames  = kTier0NominalAttackFrames;   // 132
+    z.play.adsr.decayFrames   = kTier0NominalDecayFrames;    // 0
+    z.play.adsr.sustainLevel  = kTier0NominalSustainLevel;   // 1.0
+    z.play.adsr.releaseFrames = kTier0NominalReleaseFrames;  // 2646
+    const DecodedZonePcm pcm{{0.5f}, 48000};  // 48k WAV
+    const Keymap km = buildZonedKeymap({z}, {pcm});
+    CHECK(km.samples.size() == 1);
+    if (km.samples.empty()) return;
+    const AdsrParams& a = km.samples[0].play.adsr;
+    CHECK(a.attackFrames  == 144);   // round(132 * 48000.0 / 44100.0)
+    CHECK(a.decayFrames   == 0);     // 0 * factor = 0
+    CHECK(a.sustainLevel  == 1.0);   // level, not rescaled
+    CHECK(a.releaseFrames == 2880);  // round(2646 * 48000.0 / 44100.0)
+}
+
+// buildZonedKeymap must NOT rescale a zone whose adsrNeedsRateResolve is false —
+// those frame counts are explicitly user-authored at the DAW's rate.
+static void testBuildZonedKeymapDoesNotRescaleV4Adsr() {
+    ResolvedZone z;
+    z.lowNote = 0; z.highNote = 127; z.rootNote = 60;
+    z.adsrNeedsRateResolve = false;  // v4 blob or user-edited — do not rescale
+    z.play.adsr.attackFrames  = 441;   // 0.01 s at 44100 Hz (non-nominal)
+    z.play.adsr.decayFrames   = 4410;
+    z.play.adsr.sustainLevel  = 0.7;
+    z.play.adsr.releaseFrames = 8820;
+    const DecodedZonePcm pcm{{0.5f}, 48000};  // 48k WAV — rescale would change values
+    const Keymap km = buildZonedKeymap({z}, {pcm});
+    CHECK(km.samples.size() == 1);
+    if (km.samples.empty()) return;
+    const AdsrParams& a = km.samples[0].play.adsr;
+    CHECK(a.attackFrames  == 441);    // unchanged (not rescaled)
+    CHECK(a.decayFrames   == 4410);
+    CHECK(a.sustainLevel  == 0.7);
+    CHECK(a.releaseFrames == 8820);
 }
 
 int main() {
@@ -1249,6 +1327,10 @@ int main() {
     testPlayParamsThroughComponentEnvelope();
     testFullAdsrV4RoundTrip();
     testV3BlobLiftsAdsrToNominalDefaults();
+    testV4BlobClearsAdsrNeedsRateResolve();
+    testBuildTier0KeymapRescalesAdsrAt48k();
+    testBuildZonedKeymapRescalesNominalAdsrAt48k();
+    testBuildZonedKeymapDoesNotRescaleV4Adsr();
     testComponentStateRoundTrip();
     testComponentStateLoopStartRoundTrip();
     testComponentStateSelectionOnlyNoZones();