FastLED Platform: Teensy LC (KL26)

Teensy LC (MKL26Z64) support.

Files (quick pass)

• fastled_arm_kl26.h: Aggregator; includes pin/SPI/clockless.
• fastpin_arm_kl26.h: Pin helpers.
• fastspi_arm_kl26.h: SPI output backend.
• clockless_arm_kl26.h: Clockless driver for LC.
• ws2812serial_controller.h (via k20 include): Serial WS2812 controller reuse.
• led_sysdefs_arm_kl26.h: System defines for KL26.

Notes:

• LC has tighter timing/memory limits; keep critical sections minimal.
• Verify FASTLED_USE_PROGMEM and interrupt policy per toolchain; defaults may differ between cores.

Optional feature defines

• FASTLED_USE_PROGMEM: Default 1 on LC cores.
• FASTLED_ALLOW_INTERRUPTS: Default 1. Enables FASTLED_ACCURATE_CLOCK.
• FASTLED_SPI_BYTE_ONLY: Present in sysdefs indicating SPI byte granularity optimization.

Define before including FastLED.h.