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>

celery_app.py

@@ -1,8 +1,8 @@
 """
 Art DAG Celery Application
 
-Distributed rendering for the Art DAG system.
-Uses the foundational artdag language from GitHub.
+Streaming video rendering for the Art DAG system.
+Uses S-expression recipes with frame-by-frame processing.
 """
 
 import os
@@ -14,7 +14,7 @@ app = Celery(
     'art_celery',
     broker=REDIS_URL,
     backend=REDIS_URL,
-    include=['legacy_tasks', 'tasks', 'tasks.analyze', 'tasks.execute', 'tasks.orchestrate', 'tasks.execute_sexp']
+    include=['tasks', 'tasks.streaming']
 )
 
 app.conf.update(