Pinscope 0.1.0 beta

First beta. Android 12+; the on-phone compiler needs a 64-bit ARM device.

• Live AR pin labels on the Mega 2560 (ships trained on the ELEGOO board; learns others from one photo)
• Code editor with an offline on-phone compiler (GCC 15), upload over USB OTG with automatic backup
• Simulator: real ATmega2560 emulation, 31 parts including an oscilloscope probe and RC filter, mistake warnings, speed control
• USB bench: serial monitor and plotter, Firmata pin control, voltmeter, oscilloscope with signal generator and lab demos, logic monitor, PWM and servo testers
• Pen support and tablet layout

Beta: the scope's signal generator and lab demos have not yet been tested on hardware.