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/tile_grid.sexp

@@ -1,4 +1,5 @@
 ;; Tile Grid effect - tiles image in grid
+(require-primitives "geometry" "image")
 
 (define-effect tile_grid
   :params (
@@ -6,11 +7,11 @@
     (cols :type int :default 2 :range [1 10])
     (gap :type int :default 0 :range [0 50])
   )
-  (let* ((w (width frame))
-         (h (height frame))
+  (let* ((w (image:width frame))
+         (h (image:height frame))
          (tile-w (floor (/ (- w (* gap (- cols 1))) cols)))
          (tile-h (floor (/ (- h (* gap (- rows 1))) rows)))
-         (tile (resize frame tile-w tile-h "area"))
+         (tile (image:resize frame tile-w tile-h "area"))
          (result (make-image w h (list 0 0 0))))
     (begin
       ;; Manually place tiles using nested iteration