feat ✨: Added .gitignore, README files, partitions, build options, dependencies, and configuration for ESP32-S3 development board using Arduino.

- Added `.gitignore` file to exclude unnecessary build and system files.
- Summary: Added a README file for project headers, improving organization and management of header files in the source codebase.
- Added a README file in the lib directory for project-specific libraries.
- Added new partitions to `partitions.csv`.
- The `git diff` output updates the `platformio.ini` file to include new build and upload options, dependencies, and configuration for an ESP32-S3 development board using Arduino.
- The user has added a new `main.cpp` file, added I2S and FFT functionality to it, and defined a function to calculate the frequency and convert it to a MIDI note number.
- Added a new README file in the `test` directory for PlatformIO Unit Testing.

src/main.cpp

@@ -0,0 +1,88 @@
+#include "AudioTools.h"
+// #include "AudioTools/AudioLibs/AudioI2SStream.h"
+#include "AudioTools/AudioLibs/AudioRealFFT.h" // or AudioKissFFT
+
+I2SStream i2sStream;              // I2S input stream for INMP441
+AudioRealFFT fft;                // FFT analyzer
+StreamCopy copier(fft, i2sStream);  // copy I2S mic to FFT
+
+int channels = 1;                // INMP441 is mono
+int samples_per_second = 11025;
+int bits_per_sample = 32;        // INMP441 sends 24-bit data in 32-bit words
+
+const char* solfegeName(uint8_t midiNote) {
+    static const char* solfegeNames[] = {
+        "Do", "Do#", "Re", "Re#", "Mi", "Fa", "Fa#", "Sol", "Sol#", "La", "La#", "Si"
+    };
+    return solfegeNames[midiNote % 12];
+}
+
+void fftResult(AudioFFTBase &fft) {
+    float diff;
+    auto result = fft.result();
+
+    if (result.magnitude > 100) {  // avoid noise floor
+        float magnitude_dB = 20.0 * log10(result.magnitude);
+        float freq = result.frequency;
+
+        // MIDI note number
+        int midiNote = round(69 + 12.0 * log2(freq / 440.0));
+        const char* solfege = solfegeName(midiNote);
+        int octave = (midiNote / 12) - 1;
+
+        Serial.print(freq, 2);
+        Serial.print(" Hz | ");
+
+        Serial.print("MIDI ");
+        Serial.print(midiNote);
+        Serial.print(" | ");
+
+        Serial.print("Note: ");
+        Serial.print(result.frequencyAsNote(diff));
+        Serial.print(" | ");
+
+        Serial.print("Solfège: ");
+        Serial.print(solfege);
+        Serial.print(octave);
+
+        Serial.print(" | dB: ");
+        Serial.print(magnitude_dB, 2);
+
+        Serial.print(" | Diff: ");
+        Serial.println(diff, 2);
+    }
+}
+
+
+void setup() {
+  Serial.begin(115200);
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Warning);
+
+  // Configure I2SStream for INMP441
+  auto cfg = i2sStream.defaultConfig(RX_MODE);
+  cfg.i2s_format = I2S_STD_FORMAT;
+  cfg.bits_per_sample = bits_per_sample;
+  cfg.channels = channels;
+  cfg.sample_rate = samples_per_second;
+  cfg.is_master = true;
+  cfg.pin_bck = 8;     // SCK
+  cfg.pin_ws = 9;      // WS
+  cfg.pin_data = 10;   // SD
+  i2sStream.begin(cfg);
+
+  // Configure FFT
+  auto tcfg = fft.defaultConfig();
+  tcfg.length = 8192;    // 186ms @ 11kHz minimun C2 theoretical
+  tcfg.channels = channels;
+  tcfg.sample_rate = samples_per_second;
+  tcfg.bits_per_sample = bits_per_sample;
+  tcfg.callback = &fftResult;
+  fft.begin(tcfg);
+
+  Serial.println("Setup complete. Listening...");
+
+}
+
+void loop() {
+  copier.copy();  // Stream mic data into FFT processor
+}