add nix fmt formatter (ruff format + check --fix)

ruff format + lint fixes

Diff against upstream, per-commit view, fetch support, fix </script> XSS in diff JSON

feat: archive & delete tickets with .pi backup

Diff view: include unstaged and untracked files against merge-base

Enable tmux tests in nix check by adding tmux to build inputs

Set tmux env only on session create, not on reconnect

Make ticket title immutable, store dir_name at creation

Fix bare clone: configure remote tracking refspec

tmux: remove send-keys hack for setting env in running sessions

Use human-friendly ticket workspace names: <slug>-<short-id>

Start tmux in ticket workspace dir (worktrees/<ticket-id>/)

Start tmux session in worktree directory when repo assigned

Fix terminal: set TERM=xterm-256color in pty fork, accept WS before tmux

Add POST /api/auth/setup bootstrap endpoint