Replace batch DAG system with streaming architecture

- Remove legacy_tasks.py, hybrid_state.py, render.py
- Remove old task modules (analyze, execute, execute_sexp, orchestrate)
- Add streaming interpreter from test repo
- Add sexp_effects with primitives and video effects
- Add streaming Celery task with CID-based asset resolution
- Support both CID and friendly name references for assets
- Add .dockerignore to prevent local clones from conflicting

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

sexp_effects/effects/invert.sexp

@@ -0,0 +1,9 @@
+;; Invert effect - inverts all colors
+;; Uses vectorized invert-img primitive for fast processing
+;; amount param: 0 = no invert, 1 = full invert (threshold at 0.5)
+
+(require-primitives "color_ops")
+
+(define-effect invert
+  :params ((amount :type float :default 1 :range [0 1]))
+  (if (> amount 0.5) (color_ops:invert-img frame) frame))