v4.1.5

Sync with upstream (77 commits) + Native task conversion + Release workflow

Core changes:

• Eliminated all TodoWrite → uses TaskCreate/TaskUpdate throughout
• Added /release skill for full release workflow

Skills updated:

• subagent-driven-development: native tasks in flowchart
• using-superpowers: TaskCreate in flowchart
• writing-skills: TaskCreate in checklist instruction
• release: NEW - full release workflow with Opus subagent research

Upstream merged:

• Worktree requirement for subagent-driven-development and executing-plans
• Main branch protection warnings