Sprint 1: Add AudioAnalyser.h stub

Source/AudioAnalyser.h

@@ -0,0 +1,11 @@
+#pragma once
+
+// Phase 2 stub — will be implemented in Sprint 4
+// Real-time audio analysis: LUFS, FFT bands, stereo width, True Peak
+
+class AudioAnalyser
+{
+public:
+    AudioAnalyser() = default;
+    ~AudioAnalyser() = default;
+};