v0.4.3 : persistance du theme actif choisi

- le REPL 'theme <name>' applique ET sauvegarde le theme (settings.theme dans le fichier de config actif, cree s'il manque) via persist_setting
- correction racine : config::merge ignorait settings.theme - la valeur persistee n etait jamais relue au chargement, le theme par defaut etait toujours reapplique apres un redemarrage
- 'am --theme <name>' reste un one-shot ; config set settings.theme <nom> fonctionne egalement
- aides mises a jour (banniere, help theme)
- tests de persistance + relecture au demarrage, man pages regenerees, version 0.4.3

src/repl.rs

@@ -706,7 +706,7 @@ pub fn banner_box(
         rows.push(inner(dim(&line, theme, color)));
     }
     rows.push(inner(dim(
-        "  'am --theme <name>' to switch · settings.theme in the config",
+        "  'theme <name>' to switch (saved) · 'am --theme <name>' for a one-shot",
         theme,
         color,
     )));
@@ -1831,6 +1831,15 @@ fn theme_command(app: &App, arg: Option<&str>) {
         Some(name) => match crate::theme::find(name) {
             Some(t) => {
                 app.set_theme(t);
+                // Persist the choice (settings.theme in the active config
+                // file) so it survives an exit and restart.
+                if let Err(e) =
+                    crate::commands::config_cmd::persist_setting(app, "settings.theme", t.name)
+                {
+                    app.log.error(format!(
+                        "theme applied for this session, but it could not be saved to the config: {e:#}"
+                    ));
+                }
                 let color = app.color();
                 println!(
                     "{} {}",
@@ -1871,9 +1880,7 @@ fn print_theme_status(app: &App) {
     println!("  {}", theme.dimmed(&format!("⇄ {}", others.join(" · "))));
     println!(
         "  {}",
-        theme.dimmed(
-            "'theme <name>' to switch · '--theme <name>' or settings.theme to change the default"
-        )
+        theme.dimmed("'theme <name>' to switch (saved to the config) · 'am --theme <name>' for a one-shot")
     );
 }