v0.9.0

Procedural clips: script a flame, smoke, or energy effect instead of sculpting
it frame by frame.

Added

• Procedural clip generator (Rhai). A clip can be driven by an embedded
  Rhai script that fills its frames — ideal for dynamic
  effects that are tedious to animate by hand:
  • Imperative API — the script body runs once per frame with globals
    (frame, frames, t, w/h/d) and flat helpers: set / get,
    sphere, box, rgb / hsv, a stable noise field, fractal fbm, and a
    per-frame rand.
  • Presets — Flame, Smoke, Energy, Plasma, and Sparkle, loadable as a
    starting point (and a live API example).
  • Editing — a floating, syntax-highlighted script window with an API
    cheat-sheet, frame-count and seed controls, and an Auto toggle that
    regenerates a short moment after edits settle for a near-live preview.
  • Deterministic & safe — the same seed yields the same clip; scripts are
    sandboxed (no I/O) and capped against runaway loops.
  • The script + parameters are saved in the .demiurg project; a procedural
    clip exports to .rvc (and drops onto bones as a clip layer) like any other.