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>

.dockerignore

@@ -0,0 +1,22 @@
+# Don't copy local clones - Dockerfile will clone fresh
+artdag-effects/
+
+# Python cache
+__pycache__/
+*.py[cod]
+*.egg-info/
+.pytest_cache/
+
+# Virtual environments
+.venv/
+venv/
+
+# Local env
+.env
+
+# Git
+.git/
+
+# IDE
+.vscode/
+.idea/