Initial commit — car parking distance sensor

ESP32-C3 Zero + VL53L1X ToF sensor + 3x LEDs with WiFi AP web calibration UI,
rolling average smoothing, auto-sleep, and NVS persistence.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

platformio.ini

@@ -0,0 +1,12 @@
+; PlatformIO Project Configuration File
+; Car Parking Distance Sensor
+; ESP32-C3 Zero + VL53L1X ToF sensor + 3x LEDs (green/yellow/red)
+
+[env:esp32-c3-devkitm-1]
+platform = espressif32
+board = esp32-c3-devkitm-1
+framework = arduino
+lib_deps = pololu/VL53L1X@^1.3.1
+monitor_speed = 115200
+upload_speed = 921600
+build_flags = -DARDUINO_USB_MODE=1 -DARDUINO_USB_CDC_ON_BOOT=1