shell -- team aliases and ops helper functions

Why the team uses it: a small, shared set of shell helpers so everyone's muscle memory transfers between machines and screen-shares. Deliberately minimal -- this is a baseline, not a dotfiles framework.

What this pack installs:

• install-010-fence.sh -- adds ONE fenced block to ~/.bashrc that sources files/*.sh from the toolkit clone. git pull in the toolkit updates the helpers live; re-running the installer replaces the fence in place (never duplicates it). Your own ~/.bashrc content outside the fence is untouched.

Provided helpers:

• ts <name> -- create-or-attach a tmux session (pairs with the tmux pack)
• tls -- list tmux sessions
• mkcd <d> -- mkdir -p and cd
• aliases: ll, la, gs (git status --short), gl (git log oneline)

House rule: personal aliases live in your own dotfiles OUTSIDE the fence. Additions to the team set go through PR so everyone gets them.