feat: add per-pane default foreground/background color support (#4737)

* feat: add per-pane default foreground/background color support

Add per-pane default foreground and background colors, configurable
through four surfaces:

- OSC 10/11 escape sequences (set/query) and OSC 110/111 (reset)
- CLI action: zellij action set-pane-color --pane-id <id> --fg/--bg
- Layout config: default_fg/default_bg properties on pane nodes
- Plugin API: set_pane_color() SDK function and PaneInfo read-side

Colors are applied at render time as a fallback when cells have no
explicit foreground/background, without mutating stored grid data.

Closes #4712

* refactor: address review feedback for pane color support

- Extract adjust_styles_for_custom_bg_fg in output/mod.rs
- Move color parsing (xparse_color) from tab into Grid
- Move color serialization (ansi_code_to_color_string) into Grid
- Pane trait now uses Option<String> for color getters/setters
- Add colors to session serialization (dump-layout)
- Add default_fg/default_bg to protobuf IPC schema to fix
  layout-in-session color loss
- Update example layout with tab-bar and status-bar

* fix stack overflow and ordering

* rustfmt

* update e2e snapshots

---------

Co-authored-by: Karl Bunch <karl@karlbunch.com>
Co-authored-by: Aram Drevekenin <aram@poor.dev>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/main.rs b/src/main.rs
index 581fff52..1a0db7e1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,8 +21,8 @@ fn main() {
 
     {
         let config = Config::try_from(&opts).ok();
-        if let Some(Command::Sessions(Sessions::Action(cli_action))) = opts.command {
-            commands::send_action_to_session(cli_action, opts.session, config);
+        if let Some(Command::Action(cli_action)) = opts.command {
+            commands::send_action_to_session(*cli_action, opts.session, config);
             std::process::exit(0);
         }
         if let Some(Command::Sessions(Sessions::Run {