fix: restore full terminal width in split panes

Use the outer terminal panel bounds for PTY resizing while keeping per-pane bounds for focus and input handling. This prevents split panes from being resized a second time to half width.

src/app/mod.rs

@@ -238,6 +238,7 @@ pub(crate) struct Ashell {
     pub(crate) system_status: Option<SharedString>,
     pub(crate) pane_root: PaneLayout,
     pub(crate) focused_pane_path: Vec<usize>,
+    pub(crate) terminal_panel_bounds: Option<Bounds<Pixels>>,
     pub(crate) terminal_bounds: HashMap<String, Bounds<Pixels>>,
     pub(crate) terminal_selecting: bool,
     pub(crate) dragging_splitter: Option<(Vec<usize>, usize)>, // (parent_path, child_index)
@@ -425,6 +426,7 @@ impl Ashell {
             active_group: None,
             pane_root: PaneLayout::Single(String::new()),
             focused_pane_path: Vec::new(),
+            terminal_panel_bounds: None,
             selector_selection: 0,
             workspace_panels,
             body_panels,

src/app/ui.rs

@@ -1692,10 +1692,16 @@ impl Ashell {
     fn render_terminal_panel(&mut self, cx: &mut Context<Self>) -> impl IntoElement {
         let has_active = self.active_tab.is_some();
         let pane_tree = self.pane_root.clone();
+        let view = cx.entity();
 
         v_flex().size_full().child(
             div()
                 .size_full()
+                .on_prepaint(move |bounds, _window, cx| {
+                    let _ = view.update(cx, |this, _| {
+                        this.terminal_panel_bounds = Some(bounds);
+                    });
+                })
                 .overflow_hidden()
                 .track_focus(&self.focus_handle)
                 .key_context(TERMINAL_KEY_CONTEXT)

src/session/mod.rs

@@ -875,16 +875,11 @@ impl Ashell {
             .first()
             .map(|size| size.as_f32())
             .unwrap_or(SIDEBAR_WIDTH);
-        let terminal_bounds = self
-            .active_tab
-            .as_ref()
-            .and_then(|tab_id| self.terminal_bounds.get(tab_id));
 
-        // Prefer the measured terminal element bounds when we already have
-        // them. That keeps the PTY sized to the real visible content area,
-        // instead of relying on a conservative viewport heuristic that can
-        // leave several rows unused at the bottom.
-        let (width, height) = if let Some(bounds) = terminal_bounds {
+        // Use the whole terminal panel bounds for PTY sizing.
+        // Individual pane bounds are smaller when split, so using them here
+        // would shrink the root PTY dimensions a second time.
+        let (width, height) = if let Some(bounds) = self.terminal_panel_bounds {
             (bounds.size.width.as_f32(), bounds.size.height.as_f32())
         } else {
             let terminal_height = self