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/mirror.sexp

@@ -0,0 +1,33 @@
+;; Mirror effect - mirrors half of image
+(require-primitives "geometry" "image")
+
+(define-effect mirror
+  :params (
+    (mode :type string :default "left_right")
+  )
+  (let* ((w (image:width frame))
+         (h (image:height frame))
+         (hw (floor (/ w 2)))
+         (hh (floor (/ h 2))))
+    (cond
+      ((= mode "left_right")
+       (let ((left (image:crop frame 0 0 hw h))
+             (result (copy frame)))
+         (paste result (geometry:flip-img left "horizontal") hw 0)))
+
+      ((= mode "right_left")
+       (let ((right (image:crop frame hw 0 hw h))
+             (result (copy frame)))
+         (paste result (geometry:flip-img right "horizontal") 0 0)))
+
+      ((= mode "top_bottom")
+       (let ((top (image:crop frame 0 0 w hh))
+             (result (copy frame)))
+         (paste result (geometry:flip-img top "vertical") 0 hh)))
+
+      ((= mode "bottom_top")
+       (let ((bottom (image:crop frame 0 hh w hh))
+             (result (copy frame)))
+         (paste result (geometry:flip-img bottom "vertical") 0 0)))
+
+      (else frame))))