Add .tool-versions file and declare board_config extern

Introduces a .tool-versions file specifying Python 3.11.9 for environment consistency. Also adds an extern declaration for HardwareConfig board_config in vibration_pwm.cpp to resolve linkage or visibility issues.

Author: zjwhitehead

.tool-versions

@@ -0,0 +1 @@
+python 3.11.9

src/sp140/vibration_pwm.cpp

@@ -2,6 +2,8 @@
 #include "sp140/esp32s3-config.h"
 #include "sp140/lvgl/lvgl_updates.h"
 
+extern HardwareConfig board_config;
+
 // Pin is configured via s3_config.vibe_pwm
 const int VIBE_PWM_FREQ = 1000;  // Adjust as needed
 const int VIBE_PWM_RESOLUTION = 8;  // 8-bit resolution