feat(audio): Implement real-time spectrogram synthesizer

Adds a multi-voice, real-time audio synthesis engine that generates sound from spectrogram data using an Inverse Discrete Cosine Transform (IDCT).

Key features:
- A thread-safe, double-buffered system for dynamically updating spectrograms in real-time without interrupting audio playback.
- Core DSP components: FDCT, IDCT, and Hamming window functions.
- A simple sequencer in the main loop to demonstrate scripted audio events and dynamic updates.
- Unit tests for the new synth engine and Hamming window, integrated with CTest.
- A  file documenting the build process, features, and how to run tests.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/audio/window.cpp b/src/audio/window.cpp
new file mode 100644
index 0000000..3f36480
--- /dev/null
+++ b/src/audio/window.cpp
@@ -0,0 +1,9 @@
+#include "window.h"
+#include "util/math.h"
+#include <math.h>
+
+void hamming_window_512(float window[WINDOW_SIZE]) {
+    for (int i = 0; i < WINDOW_SIZE; ++i) {
+        window[i] = 0.54f - 0.46f * cosf(2.0f * PI * i / (WINDOW_SIZE - 1));
+    }
+}