S12: store wall-clock ADSR/pitch-env as seconds, resolve to frames at live rate

Kill kTier0Nominal*, adsrNeedsRateResolve, tier0Adsr, gateAdsr. Zones payload v5 carries
seconds; v3 legacy reads convert at the frozen authoring rate; v4 (branch-only) dropped.
Editor sliders now seconds. Engine takes frames resolved at keymap build.

src/vst/reasampler_processor.h

@@ -50,11 +50,11 @@ struct LoadedInstrument {
     VoiceEngine engine;
     std::uint64_t installedAt = 0;  // reload generation at which this was installed
 
-    LoadedInstrument(Keymap km, std::size_t maxVoices, const AdsrParams& adsr,
+    LoadedInstrument(Keymap km, std::size_t maxVoices,
                      std::uint64_t gen, std::size_t preserveVoiceCap = 0,
                      std::int64_t preserveWindowFrames = 0)
         : keymap(std::move(km)),
-          engine(maxVoices, keymap, adsr, preserveVoiceCap, preserveWindowFrames),
+          engine(maxVoices, keymap, preserveVoiceCap, preserveWindowFrames),
           installedAt(gen) {}
 
     LoadedInstrument(const LoadedInstrument&) = delete;