Add generic streaming interpreter with configurable sources/audio

- Add stream_sexp_generic.py: fully generic sexp interpreter
- Add streaming primitives for video sources and audio analysis
- Add config system for external sources and audio files
- Add templates for reusable scans and macros
- Fix video/audio stream mapping in file output
- Add dynamic source cycling based on sources array length
- Remove old Python effect files (migrated to sexp)
- Update sexp effects to use namespaced primitives

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sexp_effects/effects/swirl.sexp

@@ -1,4 +1,5 @@
 ;; Swirl effect - spiral vortex distortion
+(require-primitives "geometry" "image")
 
 (define-effect swirl
   :params (
@@ -8,9 +9,9 @@
     (center_y :type float :default 0.5 :range [0 1])
     (falloff :type string :default "quadratic")
   )
-  (let* ((w (width frame))
-         (h (height frame))
+  (let* ((w (image:width frame))
+         (h (image:height frame))
          (cx (* w center_x))
          (cy (* h center_y))
-         (coords (swirl-displace w h strength radius cx cy falloff)))
-    (remap frame (coords-x coords) (coords-y coords))))
+         (coords (geometry:swirl-coords w h strength radius cx cy falloff)))
+    (geometry:remap frame (geometry:coords-x coords) (geometry:coords-y coords))))