Initial import: robot firmware + PlatformIO two-env scaffold

Robot-side firmware (Teensy 4.0) imported unchanged as extracted.
platformio.ini defines [env:robot] (teensy40) and [env:remote]
(teensy41); scripts/select_src_dir.py points each env at its own
sketch folder so robot/ and remote/ stay Arduino-style sketches.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-current/.gitignore

@@ -0,0 +1,28 @@
+# PlatformIO
+.pio/
+.pioenvs/
+.piolibdeps/
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch/
+
+# Arduino IDE / arduino-cli build output
+build/
+*.elf
+*.hex
+*.bin
+*.map
+*.o
+*.d
+
+# Nextion Editor build output (keep the .HMI source, ignore compiled .tft)
+*.tft
+
+# OS / editor noise
+.DS_Store
+Thumbs.db
+desktop.ini
+*.swp
+*~
+__pycache__/