add generative evolution, cross-mod and reverb FX; expand preset bank

- 4 new params (xmod/xmix/evolve/warp) with free-running brownian evolution
- evolution: tune drift, osc2 detune sway, osc-mix crossfade, filter cutoff
  wander, resonance growl, warp drive/bias, cross-mod bloom
- per-voice unison detune spread for fat stacks
- FX engine: 3-tap ensemble chorus, filtered-feedback ping-pong delay,
  Schroeder hall reverb; new FX types 4-7 (REV HALL/ENS+REV/DLY+REV/CATHEDRAL)
- 195 presets: 40-field realignment, genre-tuned FX identities, showcase eval
- calibrate banks vs attack-inclusive peak (median 0.263); fix square-LFO
  on filter sustain collapse

Source/PluginProcessor.h

@@ -22,7 +22,7 @@ public:
     const juce::String getName() const override;
     bool acceptsMidi() const override           { return true; }
     bool producesMidi() const override          { return false; }
-    double getTailLengthSeconds() const override { return prm::delaySyncMaxTime() + 1.0; }
+    double getTailLengthSeconds() const override { return prm::delaySyncMaxTime() + 2.0; }
 
     int getNumPrograms() override;
     int getCurrentProgram() override;