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.

.gitignore

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+# PlatformIO build files
+.pio/
+.pioenvs/
+.piolibdeps/
+
+# VS Code settings
+.vscode/
+
+# PlatformIO package cache
+.platformio/
+
+# Python virtual environment
+venv/
+env/
+
+# macOS system files
+.DS_Store
+
+# Windows system files
+Thumbs.db
+
+# Compiled object files
+*.o
+*.obj
+
+# Compiled Dynamic libraries
+*.dll
+*.so
+*.dylib
+
+# Firmware binaries
+*.bin
+*.elf
+*.hex

include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the convention is to give header files names that end with `.h'.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into the executable file.
+
+The source code of each library should be placed in a separate directory
+("lib/your_library_name/[Code]").
+
+For example, see the structure of the following example libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional. for custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+Example contents of `src/main.c` using Foo and Bar:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+The PlatformIO Library Dependency Finder will find automatically dependent
+libraries by scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

partitions.csv

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+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x2F0000,
+spiffs,   data, spiffs,  0x300000,0x100000

platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:esp32-s3-devkitm-1]
+platform = espressif32
+board = esp32-s3-devkitm-1
+framework = arduino     ;, espidf
+
+board_build.arduino.memory_type = qio_qspi
+board_build.flash_mode = qio
+board_build.psram_type = qio
+board_upload.flash_size = 4MB
+board_upload.maximum_size = 4194304
+board_build.partitions = partitions.csv  # Use custom partition table
+build_flags = -DARDUINO_USB_CDC_ON_BOOT=1
+              -DBOARD_HAS_PSRAM
+              -DARDUINO_ESP32S3_DEV
+              -DBOARD_HAS_TEMP_SENSOR
+            ;   -DCONFIG_FREERTOS_HZ=1000
+            ;   -DESP_PLATFORM
+            ;   -DARDUINO_RUNNING
+board_build.filesystem = spiffs
+monitor_speed = 115200
+upload_speed = 921600
+monitor_filters = esp32_exception_decoder
+lib_deps = 
+    https://github.com/pschatzmann/arduino-audio-tools.git
+    https://github.com/pschatzmann/arduino-audio-driver.git
+    

src/main.cpp

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+#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
+}

test/README

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+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html