window navigation builtins: SPC w h/j/k/l focus, SPC w t file<->terminal

Left/Down/Up/Right run the existing focusDir (now taking the pane the
builtin ran on, so an executed name acts on ITS pane); the Ctrl-w prefix
routes through the same four builtins instead of calling focusDir itself.
Toggleterm hops between the most recently focused document and terminal
off focus_hist, the MRU the core already rebuilds each sync.

Ctrl-w stays: a tty-mode pane never sees SPC, so it is the only keyboard
way out of one. Its snapshot step now moves focus somewhere (c-w l), which
the old c-w h in that layout did not.

0 files changed, 0 insertions, 0 deletions