feat(03-02): implement animation library — 7 types with registry and factory

- AnimationBase ABC with render(t, led_count) and from_params() contract
- SolidColorAnimation: time-independent uniform fill
- ChaseAnimation: moving lit segment with forward/reverse support
- PulseAnimation: sine-wave breathing effect (speed maps to period)
- RainbowAnimation: HSV hue cycle across strip via colorsys.hsv_to_rgb
- StrobeAnimation: on/off flashing at 1-20 Hz with configurable duty cycle
- ColorWipeAnimation: progressive fill from start or end
- FireAnimation: Fire2012 algorithm with cooling/sparking/heat-to-color mapping
- ANIMATION_REGISTRY + create_animation() factory function
- All 24 tests passing

lightsync/animations/solid_color.py

@@ -0,0 +1,23 @@
+"""Solid color animation — all LEDs the same color at all times."""
+from lightsync.animations.base import AnimationBase
+
+
+class SolidColorAnimation(AnimationBase):
+    """Time-independent: all LEDs show a single solid color."""
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        return [self.color] * led_count
+
+    @classmethod
+    def from_params(cls, params: dict) -> "SolidColorAnimation":
+        color = tuple(params.get("color", [255, 255, 255]))
+        white = params.get("white", 0)
+        return cls(color=color, white=white)  # type: ignore[arg-type]