Di/fix esp32 cursor offset issue411

[DaniilSmirnov]

Summary

• Fix the misspelled Y coordinate field that prevented cursor movement from starting.
• Keep the estimated cursor position in the same units as the ESP32 firmware’s 1, 4, and 8 step commands.
• Correct horizontal and vertical movement directions.
• Make diagonal movement deterministic to reduce drift in the estimated cursor position.
• Add unit tests for movement step selection and firmware command mapping.

Validation

• ESP32 movement tests: 13 passed.
• ESLint on the changed JavaScript files passed.
• Syntax checks and git diff --check passed.

Fixes #411