49628bcc61
Implements expressive face animations with 5 core emotions (happy/sad/curious/angry/sleeping) and smooth transitions on small LCD displays. Features: - State machine with smooth 0.5s emotion transitions (ease-in-out cubic easing) - Automatic idle blinking (4-6s intervals, 100-150ms duration per blink) - UART command interface via USART3 @ 115200 (text-based protocol) - 30Hz target refresh rate via systick integration - Low-level LCD abstraction supporting monochrome and RGB565 - Rendering primitives: pixel, line (Bresenham), circle (midpoint), filled rect Architecture: - face_lcd.h/c: Hardware-agnostic framebuffer & display driver - face_animation.h/c: Emotion state machine & parameterized face rendering - face_uart.h/c: UART command parser (HAPPY/SAD/CURIOUS/ANGRY/SLEEP/NEUTRAL/BLINK/STATUS) - Unit tests (14 test cases): emotion transitions, blinking, rendering, all emotions Integration: - main.c: Added includes, initialization (servo_init), systick tick, main loop processing - Pending: LCD hardware initialization (SPI/I2C config, display controller setup) Files: 9 new (headers, source, tests, docs), 1 modified (main.c) Lines: ~1450 total (345 headers, 650 source, 350 tests, 900 docs) Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>