v0.1.3

• Add move-only Strata::FreeRTOS::CountingSemaphore ownership using xSemaphoreCreateCountingStatic() and internal Strata-backed control storage.
• Expose task and ISR take/give operations, saturation/exhaustion failure reporting, and maximum-count diagnostics.
• Add host and ESP32 backend contracts and extend the FreeRTOS source audit to reject dynamic counting-semaphore creation.
• Document counting-semaphore ownership and configuration for consuming libraries such as Signal.
• Detect ESP32 targets through either the Arduino ESP32 macro or ESP-IDF ESP_PLATFORM, so Arduino-as-component and ESP32-P4 builds select the ESP32 allocation backend instead of the generic host backend.
• Exercise the ESP32 backend contract with ESP-IDF-style platform detection and make the PIOArduino example matrix explicitly select the Arduino framework.