sl0p: serialise the pane status bar for resurrection

The status bar survived detach/reattach (it lives on Grid) but not a
serialise/restore cycle, so a resurrected pane came back blank.

It now travels the whole per-pane serialisation pipeline, mirroring the fork's
existing default_fg/default_bg: pane -> PaneLayoutMetadata ->
PaneLayoutManifest -> TiledPaneLayout -> a status_bar property in the serialised
KDL, then back through the normal layout parser and applied by LayoutApplier
when the pane is recreated.

The sanitiser moved from grid.rs into zellij-utils so both entry points share
one definition. That matters: a layout file on disk is no more trustworthy than
the escape sequence that wrote it -- it may have been hand-edited, or copied from
somewhere else -- so restored text is stripped and length-capped on the way in
just like the OSC payload was.

Verified end to end rather than by unit test alone: set the bar, waited for a
serialisation pass, confirmed status_bar="..." in session-layout.kdl, killed the
session until list-sessions reported EXITED, then attached and watched it come
back from disk. The earlier attempt only proved detach/reattach because Quit had
left the session alive.

2 files changed, 4 insertions, 0 deletions

diff --git a/zellij-server/src/tab/layout_applier.rs b/zellij-server/src/tab/layout_applier.rs
index 44e100a4..c796fa41 100644
--- a/zellij-server/src/tab/layout_applier.rs
+++ b/zellij-server/src/tab/layout_applier.rs
@@ -741,6 +741,9 @@ impl<'a> LayoutApplier<'a> {
         if layout.default_fg.is_some() || layout.default_bg.is_some() {
             new_pane.set_pane_default_colors(layout.default_fg.clone(), layout.default_bg.clone());
         }
+        if layout.status_bar.is_some() {
+            new_pane.set_status_bar_text(layout.status_bar.clone());
+        }
         if let Some(held_command) = hold_for_command {
             new_pane.hold(None, true, held_command.clone());
         }
diff --git a/zellij-server/src/tab/mod.rs b/zellij-server/src/tab/mod.rs
index 88528229..3727b2e2 100644
--- a/zellij-server/src/tab/mod.rs
+++ b/zellij-server/src/tab/mod.rs
@@ -890,6 +890,7 @@ pub trait Pane {
     fn status_bar_text(&self) -> Option<String> {
         None
     }
+    fn set_status_bar_text(&mut self, _text: Option<String>) {}
     fn stack_list_entry_label(&self) -> String {
         self.current_title()
     }