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/emboss.sexp

@@ -1,4 +1,5 @@
 ;; Emboss effect - creates raised/3D appearance
+(require-primitives "blending")
 
 (define-effect emboss
   :params (
@@ -9,4 +10,4 @@
                        (list (- strength) 1 strength)
                        (list 0 strength strength)))
          (embossed (convolve frame kernel)))
-    (blend-images embossed frame blend)))
+    (blending:blend-images embossed frame blend)))