Two forms got the pane exemption although they run the dev server without a pane.
`tmux -vL new-session run-shell ...`: in a cluster, the last option that takes a value (f, L, S, T) takes the next token, here the socket name `new-session`. A `c` anywhere in a cluster (`-c'npm run dev'`) runs a shell command without a pane.
`tmux new-session -d \; run-shell "npm run dev"`: only the first command of a sequence was checked. The sequence is now split at `;`, and it is exempt only when every command in it that runs the dev server is a pane command. This also closes the same hole for the plain `tmux new-session ... \; run-shell`, which the old regex exempted.