Initial commit: video effects processing system

Add S-expression based video effects pipeline with modular effect
definitions, constructs, and recipe files.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sexp_effects/effects/noise.sexp

@@ -0,0 +1,7 @@
+;; Noise effect - adds random noise
+;; @param amount float [0, 100] default 20
+;; Uses vectorized add-noise primitive for fast processing
+
+(define-effect noise
+  ((amount 20))
+  (add-noise frame amount))