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/cycle-crossfade.sexp

@@ -0,0 +1,65 @@
+;; cycle-crossfade template
+;;
+;; Generalized cycling zoom-crossfade for any number of video layers.
+;; Cycles through videos with smooth zoom-based crossfade transitions.
+;;
+;; Parameters:
+;;   beat-data     - beat analysis node (drives timing)
+;;   input-videos  - list of video nodes to cycle through
+;;   init-clen     - initial cycle length in beats
+;;
+;; NOTE: The parameter is named "input-videos" (not "videos") because
+;; template substitution replaces param names everywhere in the AST.
+;; The planner's _expand_slice_on injects env["videos"] at plan time,
+;; so (len videos) inside the lambda references that injected value.
+
+(deftemplate cycle-crossfade
+  (beat-data input-videos init-clen)
+
+  (slice-on beat-data
+    :videos input-videos
+    :init {:cycle 0 :beat 0 :clen init-clen}
+    :fn (lambda [acc i start end]
+      (let [beat   (get acc "beat")
+            clen   (get acc "clen")
+            active (get acc "cycle")
+            n      (len videos)
+            phase3 (* beat 3)
+            wt (lambda [p]
+              (let [prev (mod (+ p (- n 1)) n)]
+                (if (= active p)
+                  (if (< phase3 clen) 1.0
+                    (if (< phase3 (* clen 2))
+                      (- 1.0 (* (/ (- phase3 clen) clen) 1.0))
+                      0.0))
+                  (if (= active prev)
+                    (if (< phase3 clen) 0.0
+                      (if (< phase3 (* clen 2))
+                        (* (/ (- phase3 clen) clen) 1.0)
+                        1.0))
+                    0.0))))
+            zm (lambda [p]
+              (let [prev (mod (+ p (- n 1)) n)]
+                (if (= active p)
+                  ;; Active video: normal -> zoom out during transition -> tiny
+                  (if (< phase3 clen) 1.0
+                    (if (< phase3 (* clen 2))
+                      (+ 1.0 (* (/ (- phase3 clen) clen) 1.0))
+                      0.1))
+                  (if (= active prev)
+                    ;; Incoming video: tiny -> zoom in during transition -> normal
+                    (if (< phase3 clen) 0.1
+                      (if (< phase3 (* clen 2))
+                        (+ 0.1 (* (/ (- phase3 clen) clen) 0.9))
+                        1.0))
+                    0.1))))
+            new-acc (if (< (+ beat 1) clen)
+                      (dict :cycle active :beat (+ beat 1) :clen clen)
+                      (dict :cycle (mod (+ active 1) n) :beat 0
+                            :clen (+ 40 (mod (* i 7) 41))))]
+        {:layers (map (lambda [p]
+                   {:video p :effects [{:effect zoom :amount (zm p)}]})
+                 (range 0 n))
+         :compose {:effect blend_multi :mode "alpha"
+                   :weights (map (lambda [p] (wt p)) (range 0 n))}
+         :acc new-acc}))))