pub const PANE_ENV_KEEP: &[&str];Expand description
AGENTMUX_* variables permitted to reach a pane by inheritance.
Derived from an exhaustive audit of every process.env read in
backend/shellintegration/ (muxsh, muxlog, muxspect, muxopen,
lib/muxclient.mjs) plus the shell rc scripts. Each entry needs a reason;
anything without one does not belong here.