Shared ClipEvent contract for the dem0nhub video-moments ecosystem. Pure module, no executables. Sibling to @foenem_jarvis/beatlib (audio events) — clipslib is for video moments produced by skills like clip-search and consumed by feverdream, mp4x, transition-engine. Defines the ClipEvent dataclass, detector registry, JSON sidecar format (`<video>.clips.json`), and cache primitives. TRIGGER when a skill needs to detect, normalize, cache, or consume semantic video moments. Drop-in `from clipslib import ClipEvent, register, detect, read_sidecar, write_sidecar`. v0.1.0.