comp.new / comp.settings passed `frameRate` straight to
FrameRate::from_f64, so 0 (or anything below 0.0005) became a 0/1 rate
and the next frame-duration computation divided by zero, killing the
process (and an MCP session with its unsaved project); a negative rate
was accepted as-is. Scripts hit it via addComp(..., 0) or
comp.frameRate = 0. Return a parameter error like renderQueue.add's
frameRate check does.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>