Agent Skills: internal-dev-workbench

Spin up a portless + tmux dev session for the Workflow SDK that gives each git worktree isolated `<branch>.<name>.localhost` URLs for the Next.js workbench and the observability UI, plus a Claude statusline that surfaces those URLs. Use only when the user asks for a "portless dev session", a "tmux dev layout for workflow", "worktree-isolated dev URLs", or wants to wire workflow dev URLs into the Claude statusline. Do not activate for the generic "start the dev server" / "run pnpm dev" task.