Add test suite for subagent-driven-development skill

Two test projects for validating the skill with full end-to-end runs:
- go-fractals: 10 tasks, CLI tool with Sierpinski and Mandelbrot
- svelte-todo: 12 tasks, CRUD app with localStorage and Playwright

Each test has design.md, plan.md, and scaffold.sh. Run with:
  ./tests/subagent-driven-dev/run-test.sh go-fractals

tests/subagent-driven-dev/svelte-todo/scaffold.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# Scaffold the Svelte Todo test project
+# Usage: ./scaffold.sh /path/to/target/directory
+
+set -e
+
+TARGET_DIR="${1:?Usage: $0 <target-directory>}"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+# Create target directory
+mkdir -p "$TARGET_DIR"
+cd "$TARGET_DIR"
+
+# Initialize git repo
+git init
+
+# Copy design and plan
+cp "$SCRIPT_DIR/design.md" .
+cp "$SCRIPT_DIR/plan.md" .
+
+# Create initial commit
+git add .
+git commit -m "Initial project setup with design and plan"
+
+echo "Scaffolded Svelte Todo project at: $TARGET_DIR"
+echo ""
+echo "To run the test:"
+echo "  claude -p \"Execute this plan using superpowers:subagent-driven-development. Plan: $TARGET_DIR/plan.md\" --plugin-dir /path/to/superpowers"