[codex] test: include Arduino header in LPC sketches

tests/platform/lpc804/lpc804.ino

@@ -6,6 +6,8 @@
 // its own variant core (zackees/ArduinoCore-LPC8xx) provides the real
 // register-level GPIO implementation.
 
+#include <Arduino.h>
+
 #ifndef LED_BUILTIN
 #define LED_BUILTIN 0
 #endif

tests/platform/lpc845/lpc845.ino

@@ -6,6 +6,8 @@
 // its own variant core (zackees/ArduinoCore-LPC8xx) provides the real
 // register-level GPIO implementation.
 
+#include <Arduino.h>
+
 #ifndef LED_BUILTIN
 #define LED_BUILTIN 0
 #endif

tests/platform/lpc845_build_flags/src/main.ino

@@ -5,6 +5,8 @@
 // nxplpc library compile path. A working build proves the orchestrator now
 // folds `ctx.user_flags` into the `LibraryBuildEnv` flag set.
 
+#include <Arduino.h>
+
 extern void check_flag_no_op();
 
 void setup() {

tests/platform/lpc845brk/lpc845brk.ino

@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}

tests/platform/lpcxpresso804/lpcxpresso804.ino

@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}

tests/platform/lpcxpresso845max/lpcxpresso845max.ino

@@ -1,2 +1,4 @@
+#include <Arduino.h>
+
 void setup() {}
 void loop() {}