v2.3.1 - Motor and platform position PID

Add motor and platform position initialization, reset and target commands, motor position readback, and full position PID configuration with separate Kp, Ki and Kd.

Initialize velocity before position. Motor targets use continuous radians; platform targets use meters/meters/radians. Velocity initialization defaults to a 100% PWM integral contribution limit. Retune velocity gains when upgrading to firmware 2.3.1.

Connections accept protocol 2.1+. Position commands require 2.2+, and full position PID initialization requires 2.3+.

Wire buffer: full platform position PID initialization requires a 100-byte transmit buffer; 128 bytes is recommended. Configure the board's actual buffer and set KINISI_WIRE_BUFFER_SIZE to match. Commands are not split across I2C transactions.

The attached ZIP can be installed with Arduino IDE's Add .ZIP Library command and includes a motor/platform position example.

Validation: 32/64/128-byte Wire tests, production firmware interoperability, generator checks and example syntax checks passed.