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/pixelsort.sexp

@@ -0,0 +1,11 @@
+;; Pixelsort effect - glitch art pixel sorting
+
+(define-effect pixelsort
+  :params (
+    (sort_by :type string :default "lightness")
+    (threshold_low :type int :default 50 :range [0 255])
+    (threshold_high :type int :default 200 :range [0 255])
+    (angle :type int :default 0 :range [0 180])
+    (reverse :type bool :default false)
+  )
+  (pixelsort frame sort_by threshold_low threshold_high angle reverse))