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/resize-frame.sexp

@@ -0,0 +1,11 @@
+;; Resize effect - replaces RESIZE node
+;; Note: uses target-w/target-h to avoid conflict with width/height primitives
+(require-primitives "image")
+
+(define-effect resize-frame
+  :params (
+    (target-w :type int :default 640 :desc "Target width in pixels")
+    (target-h :type int :default 480 :desc "Target height in pixels")
+    (mode :type string :default "linear" :choices [linear nearest area] :desc "Interpolation mode")
+  )
+  (image:resize frame target-w target-h mode))