Wiring two ESP32s TX2->RX2 (Serial2) or TX->RX for board-to-board serial
produced no data on the receiver: classifyPin() returned 'digital' for the
UART pins, so the Interconnect never installed the byte-level UART bridge.
Two causes in boardProtocols.ts normalizePinName:
- TX/RX aliases only matched boardKind === 'esp32' exactly, missing every
variant (esp32-devkit-c-v4, esp32-cam, esp32-s3), and TX2/RX2 were not
handled at all. Resolve them via startsWith('esp32') (esp32-c3 kept
separate) and map TX2/RX2 -> GPIO17/16.
- 'GPIO17'-style labels fell into the 'GP' (RP2040) branch first, where
parseInt('IO17') = NaN swallowed them to null. Exclude 'GPIO' from the
'GP' branch so the ESP32 GPIO-prefix handling runs.
Adds esp32-uart-classify.test.ts (6 cases, green).
David Montero