v1.1: Add New Band button and FIR quality selector

- New Band button in header bar for adding EQ nodes
- FIR latency dropdown: 4096 (~46ms), 8192 (~93ms), 16384 (~186ms)
- Version bump to 1.1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Source/PluginProcessor.cpp

@@ -125,6 +125,13 @@ void InstaLPEQProcessor::updateFIR()
     firEngine.setBands (currentBands);
 }
 
+void InstaLPEQProcessor::setQuality (int fftOrder)
+{
+    firEngine.setFFTOrder (fftOrder);
+    setLatencySamples (firEngine.getLatencySamples());
+    updateFIR();
+}
+
 // ============================================================
 // State save/restore
 // ============================================================