Fix audio module: implement WAV parsing and audio playback

- Implement ParseWAVData and ParseWAVHeader in AudioLoader to properly
  parse WAV file headers (sample rate, channels, bits per sample, duration)
- Modify Load() to call ParseWAVData for WAV files during loading
- Add DecodeAudioData() to AudioSourceComponent to decode PCM bytes to float
- Update SetClip() to trigger audio decoding
- Fix ProcessAudio() to read from decoded data instead of empty output buffer
- Add WAV parsing unit tests (ParseWAV_Mono44100_16bit, ParseWAV_Stereo48000_16bit)

Fixes issues:
- AudioLoader::ParseWAVData was a stub returning true without parsing
- AudioLoader::Load didn't extract audio metadata from WAV headers
- AudioSourceComponent::ProcessAudio read from empty m_outputBuffer

All 167 tests pass.

engine/src/Resources/AudioLoader.cpp

@@ -1,10 +1,68 @@
 #include "Resources/AudioLoader.h"
 #include "Resources/ResourceManager.h"
 #include "Resources/ResourceTypes.h"
+#include <cstring>
 
 namespace XCEngine {
 namespace Resources {
 
+namespace {
+
+struct WAVHeader {
+    uint32_t sampleRate = 44100;
+    uint32_t channels = 2;
+    uint32_t bitsPerSample = 16;
+    uint32_t dataSize = 0;
+    uint32_t dataOffset = 44;
+};
+
+bool ParseWAVHeader(const uint8_t* data, size_t size, WAVHeader& header) {
+    if (size < 44) {
+        return false;
+    }
+
+    if (data[0] != 'R' || data[1] != 'I' || data[2] != 'F' || data[3] != 'F') {
+        return false;
+    }
+
+    if (data[8] != 'W' || data[9] != 'A' || data[10] != 'V' || data[11] != 'E') {
+        return false;
+    }
+
+    if (data[12] != 'f' || data[13] != 'm' || data[14] != 't' || data[15] != ' ') {
+        return false;
+    }
+
+    uint32_t subchunk1Size = *reinterpret_cast<const uint32_t*>(&data[16]);
+    if (subchunk1Size < 16) {
+        return false;
+    }
+
+    uint16_t audioFormat = *reinterpret_cast<const uint16_t*>(&data[20]);
+    if (audioFormat != 1) {
+        return false;
+    }
+
+    header.channels = *reinterpret_cast<const uint16_t*>(&data[22]);
+    header.sampleRate = *reinterpret_cast<const uint32_t*>(&data[24]);
+    header.bitsPerSample = *reinterpret_cast<const uint16_t*>(&data[34]);
+
+    if (data[36] != 'd' || data[37] != 'a' || data[38] != 't' || data[39] != 'a') {
+        return false;
+    }
+
+    header.dataSize = *reinterpret_cast<const uint32_t*>(&data[40]);
+    header.dataOffset = 44;
+
+    if (header.dataOffset + header.dataSize > size) {
+        return false;
+    }
+
+    return true;
+}
+
+} // namespace
+
 AudioLoader::AudioLoader() = default;
 
 AudioLoader::~AudioLoader() = default;
@@ -38,6 +96,12 @@ LoadResult AudioLoader::Load(const Containers::String& path, const ImportSetting
     audioClip->m_guid = ResourceGUID::Generate(path);
     
     AudioFormat format = DetectAudioFormat(path, data);
+    if (format == AudioFormat::WAV) {
+        if (!ParseWAVData(data, audioClip)) {
+            delete audioClip;
+            return LoadResult("Failed to parse WAV data");
+        }
+    }
     audioClip->SetAudioFormat(format);
     audioClip->SetAudioData(data);
     
@@ -53,6 +117,20 @@ ImportSettings* AudioLoader::GetDefaultSettings() const {
 }
 
 bool AudioLoader::ParseWAVData(const Containers::Array<Core::uint8>& data, AudioClip* audioClip) {
+    WAVHeader header;
+    if (!ParseWAVHeader(data.Data(), data.Size(), header)) {
+        return false;
+    }
+
+    audioClip->SetSampleRate(header.sampleRate);
+    audioClip->SetChannels(header.channels);
+    audioClip->SetBitsPerSample(header.bitsPerSample);
+
+    uint32_t bytesPerSample = header.bitsPerSample / 8;
+    uint32_t totalSamples = header.dataSize / (bytesPerSample * header.channels);
+    float duration = static_cast<float>(totalSamples) / (header.sampleRate * header.channels);
+    audioClip->SetDuration(duration);
+
     return true;
 }