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/crossfade-zoom.sexp

@@ -0,0 +1,25 @@
+;; Crossfade with Zoom Transition
+;;
+;; Macro for transitioning between two frames with a zoom effect.
+;; Active frame zooms out while next frame zooms in.
+;;
+;; Required context:
+;;   - zoom effect must be loaded
+;;   - blend effect must be loaded
+;;
+;; Parameters:
+;;   active-frame: current frame
+;;   next-frame: frame to transition to
+;;   fade-amt: transition progress (0 = all active, 1 = all next)
+;;
+;; Usage:
+;;   (include :path "../templates/crossfade-zoom.sexp")
+;;   ...
+;;   (crossfade-zoom active-frame next-frame 0.5)
+
+(defmacro crossfade-zoom (active-frame next-frame fade-amt)
+  (let [active-zoom (+ 1.0 fade-amt)
+        active-zoomed (zoom active-frame :amount active-zoom)
+        next-zoom (+ 0.1 (* fade-amt 0.9))
+        next-zoomed (zoom next-frame :amount next-zoom)]
+    (blend active-zoomed next-zoomed :opacity fade-amt)))