feat(skills): add p5js creative coding skill

Production pipeline for interactive and generative visual art using p5.js.

Covers 7 modes: generative art, data visualization, interactive experiences,
animation/motion graphics, 3D scenes, image processing, and audio-reactive.

Includes:
- SKILL.md with creative standard, pipeline, and critical implementation notes
- 10 reference files covering core API, shapes, visual effects (noise, flow
  fields, particles, domain warp, attractors, L-systems, circle packing,
  bloom, reaction-diffusion), animation (easing, springs, state machines,
  scene transitions), typography, color systems, WebGL/3D/shaders,
  interaction, and comprehensive export pipeline
- Deterministic headless frame capture via Puppeteer (noLoop + redraw)
- ffmpeg render pipeline for MP4 video export
- Per-clip architecture for multi-scene video production
- Interactive viewer template with seed navigation and parameter controls
- Performance guidance: FES disable, Math.* hot loops, per-pixel budgets
- Addon library coverage: p5.brush, p5.grain, CCapture.js, p5.js-svg
- fxhash/Art Blocks generative platform conventions
- p5.js 2.0 migration guide (async setup, OKLCH, splineVertex, shader.modify)
- 13 documented common mistakes and troubleshooting patterns

17 files, ~5,900 lines.

skills/creative/p5js/scripts/serve.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# p5.js Skill — Local Development Server
+# Serves the current directory over HTTP for loading local assets (fonts, images)
+#
+# Usage:
+#   bash scripts/serve.sh [port] [directory]
+#
+# Examples:
+#   bash scripts/serve.sh                    # serve CWD on port 8080
+#   bash scripts/serve.sh 3000               # serve CWD on port 3000
+#   bash scripts/serve.sh 8080 ./my-project  # serve specific directory
+
+PORT="${1:-8080}"
+DIR="${2:-.}"
+
+echo "=== p5.js Dev Server ==="
+echo "Serving: $(cd "$DIR" && pwd)"
+echo "URL:     http://localhost:$PORT"
+echo "Press Ctrl+C to stop"
+echo ""
+
+cd "$DIR" && python3 -m http.server "$PORT" 2>/dev/null || {
+  echo "Python3 not found. Trying Node.js..."
+  npx serve -l "$PORT" "$DIR" 2>/dev/null || {
+    echo "Error: Need python3 or npx (Node.js) for local server"
+    exit 1
+  }
+}