Add modular primitive libraries and fix Symbol class compatibility

- Add primitive_libs/ with modular primitive loading (core, math, image,
  color, color_ops, filters, geometry, drawing, blending, arrays, ascii)
- Effects now explicitly declare dependencies via (require-primitives "...")
- Convert ascii-fx-zone from hardcoded special form to loadable primitive
- Add _is_symbol/_is_keyword helpers for duck typing to support both
  sexp_effects.parser.Symbol and artdag.sexp.parser.Symbol classes
- Auto-inject _interp and _env for primitives that need them
- Remove silent error swallowing in cell_effect evaluation

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

sexp_effects/effects/ascii_fx_zone.sexp

@@ -1,5 +1,8 @@
 ;; Composable ASCII Art with Per-Zone Expression-Driven Effects
-;;
+;; Requires ascii primitive library for the ascii-fx-zone primitive
+
+(require-primitives "ascii")
+
 ;; Two modes of operation:
 ;;
 ;; 1. EXPRESSION MODE: Use zone-* variables in expression parameters

sexp_effects/effects/blur.sexp

@@ -1,5 +1,7 @@
 ;; Blur effect - gaussian blur
 
+(require-primitives "filters" "math")
+
 (define-effect blur
   :params (
     (radius :type int :default 5 :range [1 50])

sexp_effects/effects/brightness.sexp

@@ -1,6 +1,8 @@
 ;; Brightness effect - adjusts overall brightness
 ;; Uses vectorized adjust primitive for fast processing
 
+(require-primitives "color_ops")
+
 (define-effect brightness
   :params (
     (amount :type int :default 0 :range [-255 255])

sexp_effects/effects/contrast.sexp

@@ -1,6 +1,8 @@
 ;; Contrast effect - adjusts image contrast
 ;; Uses vectorized adjust primitive for fast processing
 
+(require-primitives "color_ops")
+
 (define-effect contrast
   :params (
     (amount :type int :default 1 :range [0.5 3])

sexp_effects/effects/hue_shift.sexp

@@ -1,6 +1,8 @@
 ;; Hue shift effect - rotates hue values
 ;; Uses vectorized shift-hsv primitive for fast processing
 
+(require-primitives "color_ops")
+
 (define-effect hue_shift
   :params (
     (degrees :type int :default 0 :range [0 360])

sexp_effects/effects/invert.sexp

@@ -1,6 +1,8 @@
 ;; Invert effect - inverts all colors
 ;; Uses vectorized invert-img primitive for fast processing
 
+(require-primitives "color_ops")
+
 (define-effect invert
   :params ()
   (invert-img frame))

sexp_effects/effects/rotate.sexp

@@ -1,5 +1,7 @@
 ;; Rotate effect - rotates image
 
+(require-primitives "geometry")
+
 (define-effect rotate
   :params (
     (angle :type int :default 0 :range [-360 360])

sexp_effects/effects/saturation.sexp

@@ -1,6 +1,8 @@
 ;; Saturation effect - adjusts color saturation
 ;; Uses vectorized shift-hsv primitive for fast processing
 
+(require-primitives "color_ops")
+
 (define-effect saturation
   :params (
     (amount :type int :default 1 :range [0 3])