fix(S12 review): per-zone A/D/S/R reaches voice; zones payload v4 + v3 back-compat

Voice::start reads full zone ADSR instead of folding only holdFrames into instrument-wide gateAdsr. Wire format bumped to v4 (four new fields); v3 blobs lift A/D/S/R to kTier0Nominal* constants. Single-capture editor controls now reachable. Minor comment and geometry fixes.

tests/test_sample_map.cpp

@@ -1138,6 +1138,64 @@ static void testPlayParamsThroughComponentEnvelope() {
     CHECK(back.map.zones[0].play.pitchEngine == PitchEngine::Varispeed);
 }
 
+// --- S12 review fix (PAYLOAD v4): full A/D/S/R per-zone round-trip. ---------------------
+//
+// Before the fix, per-zone A/D/S/R (attack/decay/sustain/release) was not serialized;
+// only holdFrames was written. These two tests assert the corrected v4 path.
+
+// All five AHDSR fields (including the four new A/D/S/R) must round-trip through the v4 payload.
+static void testFullAdsrV4RoundTrip() {
+    PerformanceMap m;
+    PerformanceZone z = zone("pad", 0, 127);
+    z.play.playMode = PlayMode::Gate;
+    z.play.adsr.attackFrames  = 441;    // 0.01 s at 44100 Hz (a non-default value)
+    z.play.adsr.holdFrames    = 882;
+    z.play.adsr.decayFrames   = 4410;   // 0.1 s
+    z.play.adsr.sustainLevel  = 0.7;
+    z.play.adsr.releaseFrames = 8820;   // 0.2 s
+    z.play.pitchEngine = PitchEngine::Preserve;
+    m.zones.push_back(z);
+    const PerformanceMap back = deserializePerformance(serializePerformance(m));
+    CHECK(back.zones.size() == 1);
+    if (back.zones.size() != 1) return;
+    const AdsrParams& a = back.zones[0].play.adsr;
+    CHECK(a.attackFrames  == 441);
+    CHECK(a.holdFrames    == 882);
+    CHECK(a.decayFrames   == 4410);
+    CHECK(a.sustainLevel  == 0.7);      // exact double round-trip via bit-cast
+    CHECK(a.releaseFrames == 8820);
+    CHECK(back.zones[0].play.pitchEngine == PitchEngine::Preserve);
+}
+
+// A genuine PAYLOAD v3 blob (S15/S16 build — has holdFrames but not A/D/S/R) must lift
+// attackFrames / decayFrames / sustainLevel / releaseFrames to the tier-0 nominal defaults
+// (kTier0Nominal* constants) so the voice sounds bit-identical to the pre-fix behavior.
+// We reuse handBuildV3PayloadOneZone which emits a valid marker-versioned v3 payload.
+static void testV3BlobLiftsAdsrToNominalDefaults() {
+    // Build a PERFORMANCE blob: 4-byte kPerformanceStateVersion header + v3 zones payload.
+    // deserializePerformance strips the 4-byte header and passes the rest to readZonesPayload,
+    // which self-selects the v3 record shape from the payload marker+version — exercising the
+    // real production lift path for a user who saved on the S15 build.
+    std::vector<std::uint8_t> blob;
+    auto u32 = [&](std::uint32_t v) {
+        blob.push_back(v & 0xFF); blob.push_back((v >> 8) & 0xFF);
+        blob.push_back((v >> 16) & 0xFF); blob.push_back((v >> 24) & 0xFF);
+    };
+    u32(kPerformanceStateVersion);  // envelope version 2 header
+    const std::vector<std::uint8_t> payload = handBuildV3PayloadOneZone("old");
+    blob.insert(blob.end(), payload.begin(), payload.end());
+    const PerformanceMap back = deserializePerformance(blob);
+    CHECK(back.zones.size() == 1);
+    if (back.zones.size() != 1) return;
+    const AdsrParams& a = back.zones[0].play.adsr;
+    // holdFrames comes from the v3 record itself; A/D/S/R must lift to the nominal tier-0 values.
+    CHECK(a.holdFrames    == 2048);                         // from the hand-built v3 record
+    CHECK(a.attackFrames  == kTier0NominalAttackFrames);    // 132 (0.003 s at 44100)
+    CHECK(a.decayFrames   == kTier0NominalDecayFrames);     // 0
+    CHECK(a.sustainLevel  == kTier0NominalSustainLevel);    // 1.0
+    CHECK(a.releaseFrames == kTier0NominalReleaseFrames);   // 2646 (0.060 s at 44100)
+}
+
 int main() {
     testSelectByIdHit();
     testSelectEmptyIdIsSilence();
@@ -1189,6 +1247,8 @@ int main() {
     testPlayParamsComposeWithLoopStart();
     testPlayParamsV2BackCompatLiftsToDefaults();
     testPlayParamsThroughComponentEnvelope();
+    testFullAdsrV4RoundTrip();
+    testV3BlobLiftsAdsrToNominalDefaults();
     testComponentStateRoundTrip();
     testComponentStateLoopStartRoundTrip();
     testComponentStateSelectionOnlyNoZones();