* **Refactor**
* GPIO subsystem moved to a descriptor-based model for per-pin ownership and runtime pin management; many platform drivers now acquire/release descriptors.
* Device trees and drivers now use GPIO phandle-style pin specifications across all boards and all drivers.
* **Behavior**
* Device list now encodes per-device status (ok/disabled); boot will skip disabled devices accordingly.
* **Deprecation**
* Legacy GPIO HAL marked deprecated and replaced with descriptor-based interfaces.
* **Chores**
* Bindings and platform configs updated to the new GPIO pin-spec format.
- Add kernel support for SPI driver
- Add kernel support for UART driver
- Implemented ESP32 UART kernel driver
- Update existing UART-related code in Tactility to use new kernel driver
- Remove UART from tt::hal::Configuration
- Remove tt_hal_uart functionality but keep functions for now
- Update devicetrees for UART changes
- Kernel mutex and recursive mutex: improved locking API design
- Other kernel improvements
- Added device_exists_of_type() and device_find_by_name()
