Execute git worktree operations

Create and manage git worktrees for task-based development

Isolating task branches in separate work directories with built-in context.

• · Task ID (e.g., SCR-001)
• · Operation (create/list/status/finish/remove)

• · Worktree path, branch name, acceptance criteria, git commands

• · git worktree
• · shell scripts (wt.sh)

• · wt.sh script present
• · Task JSON file exists

• · Worktree path already exists
• · Task file missing
• · Git error

• · Task-index.json for parallel tracking
• · Unblock cascade on completion