Arduino CLI build system with HAL-based test architecture

Build and upload tool (arduino-build.sh):
- Compile, upload, and monitor via arduino-cli
- Device discovery with USB ID identification (--devices)
- Persistent reconnecting serial monitor (--watch)
- Split compile/upload workflow (--verify, --upload-only)
- First-time setup wizard (--setup)
- Comprehensive --help with troubleshooting and RedBoard specs

Testable application architecture:
- Hardware abstraction layer (lib/hal/) decouples logic from Arduino API
- Google Mock HAL for unit tests (exact call verification)
- Simulated HAL for system tests (GPIO state, virtual clock, I2C devices)
- Example I2C temperature sensor simulator (TMP102)
- Host-side test suite via CMake + Google Test (21 tests)

Example sketch:
- blink/ -- LED blink with button-controlled speed, wired through HAL

.vscode/settings.json

@@ -0,0 +1,36 @@
+{
+    "files.associations": {
+        "*.ino": "cpp"
+    },
+    "C_Cpp.default.compilerPath": "",
+    "C_Cpp.default.defines": [
+        "ARDUINO=10816",
+        "ARDUINO_AVR_UNO",
+        "ARDUINO_ARCH_AVR",
+        "__AVR_ATmega328P__",
+        "F_CPU=16000000L"
+    ],
+    "C_Cpp.default.includePath": [
+        "${workspaceFolder}/**",
+        "~/.arduino15/packages/arduino/hardware/avr/*/cores/arduino",
+        "~/.arduino15/packages/arduino/hardware/avr/*/variants/standard",
+        "~/.arduino15/packages/arduino/hardware/avr/*/libraries/**",
+        "~/Arduino/libraries/**"
+    ],
+    "C_Cpp.errorSquiggles": "enabled",
+    "C_Cpp.default.cStandard": "c11",
+    "C_Cpp.default.cppStandard": "c++11",
+    "editor.formatOnSave": false,
+    "files.trimTrailingWhitespace": true,
+    "files.insertFinalNewline": true,
+    "files.exclude": {
+        "**/*.o": true,
+        "**/*.d": true,
+        "**/*.elf": true,
+        "**/*.hex": true
+    },
+    "search.exclude": {
+        "**/build": true,
+        "/tmp/arduino-build": true
+    }
+}