Serial.begin() was hardcoded to SERIAL_8N1 across all four UART init paths
(UART0/1/2/3), with no way to override it via a build flag -- unlike SERIALBaud,
which already is. Devices using non-8N1 framing (e.g. even-parity RS232 sources)
currently can't be read correctly at all, not just unreliably: a parity mismatch
misaligns the frame, not just adds occasional noise.
Adds SERIAL_CONFIG following the existing #ifndef/#define override pattern used
throughout this codebase, defaulting to SERIAL_8N1 so existing environments are
unaffected byte-for-byte. Verified: default (SERIAL_8N1) and an override
(SERIAL_CONFIG=SERIAL_8E1) both build successfully on ESP32.
Co-authored-by: simowilso <simowilso@users.noreply.github.com>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
Couple of minor formatting changes, and extra info around HASS auto discovery. (When I fully understand it all better myself I'm happy to have a go at adding further info)
