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>

templates/standard-primitives.sexp

@@ -0,0 +1,14 @@
+;; Standard Primitives Bundle
+;;
+;; Loads all commonly-used primitive libraries.
+;; Include this at the top of streaming recipes.
+;;
+;; Usage:
+;;   (include :path "../templates/standard-primitives.sexp")
+
+(require-primitives "geometry")
+(require-primitives "core")
+(require-primitives "image")
+(require-primitives "blending")
+(require-primitives "color_ops")
+(require-primitives "streaming")