updated encoder code

[snehaashahh]

Summary

• add MT6835 encoder bring-up code that prints raw angle, radians, and status over serial
• enable CRC/status reporting and initialize SPI chip select before encoder startup
• adjust PlatformIO serial monitor and build flags for the encoder bring-up environment

Validation

• Not run locally; branch was cherry-picked onto the current WATonomous/humanoid:main and conflicts were resolved to contain only the intended encoder update.

Notes

• Created from snehaashahh/humanoid:sneha-encoder because direct push to WATonomous/humanoid still returned 403 for snehaashahh.