feat: allow configuring terminal pane borders

src/config.rs

@@ -231,6 +231,7 @@ pub struct Config {
     pub opacity: u8,
     pub profiles: BTreeMap<ProfileId, Profile>,
     pub show_headerbar: bool,
+    pub show_pane_borders: bool,
     pub use_bright_bold: bool,
     pub syntax_theme_dark: String,
     pub syntax_theme_light: String,
@@ -260,6 +261,7 @@ impl Default for Config {
             opacity: 100,
             profiles: BTreeMap::new(),
             show_headerbar: true,
+            show_pane_borders: false,
             syntax_theme_dark: COSMIC_THEME_DARK.to_string(),
             syntax_theme_light: COSMIC_THEME_LIGHT.to_string(),
             use_bright_bold: false,