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/sepia.sexp

@@ -1,9 +1,7 @@
 ;; Sepia effect - applies sepia tone
 ;; Classic warm vintage look
+(require-primitives "color_ops")
 
 (define-effect sepia
   :params ()
-  (color-matrix frame
-    (list (list 0.393 0.769 0.189)
-          (list 0.349 0.686 0.168)
-          (list 0.272 0.534 0.131))))
+  (color_ops:sepia frame))