grid: sync flowbox selection to navigator.current on Enter/t (cu0)

Arrow-key navigation in the grid moved the GtkFlowBox selection but never
updated navigator.current, so Enter (and toggling to large with t) opened
the stale current image instead of the highlighted one. _on_flow_key
emitted the activate signal directly without syncing, unlike the
double-click path (_on_child_activated) which does sync.

Add ggaze_grid_sync_current(): reads the selected flowbox child and calls
navigator_set_current_file. Call it from _on_flow_key before emitting
activate, and from _action_toggle_view's grid→large branch (then load
the now-current image). Mirrors the existing double-click sync.

0 files changed, 0 insertions, 0 deletions