fix: Worktree scripts use $(pwd) for project root

Scripts now correctly determine project root from current working
directory instead of calculating relative to script location.
This fixes the issue when scripts are called via ${CLAUDE_PLUGIN_ROOT}.

Also adds CLAUDE.md and CHANGELOG.md for development guidance.

Bumps version to 1.0.3.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

plugin/scripts/worktree-cleanup.sh

@@ -7,9 +7,8 @@ set -e
 
 FEATURE_NAME="$1"
 
-# Get project root (parent of .auto-build)
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+# Get project root from current working directory (where Claude Code is running)
+PROJECT_ROOT="$(pwd)"
 PROJECT_NAME=$(basename "$PROJECT_ROOT")
 WORKTREES_DIR="$(dirname "$PROJECT_ROOT")/ab-worktrees"
 
@@ -104,5 +103,5 @@ else
 
     echo ""
     echo "To cleanup a specific worktree:"
-    echo "  bash .auto-build/scripts/worktree-cleanup.sh <feature-name>"
+    echo "  /ab:worktree cleanup <feature-name>"
 fi