feat(profiles): add setting to toggle project switcher on main page

Add a show/hide toggle for the header project profile switcher under
the Homepage Display section in settings. Defaults to visible so
existing users keep the current behavior.

src-tauri/src/settings.rs

@@ -374,6 +374,9 @@ pub struct AppSettings {
     /// Whether to show the failover toggle independently on the main page
     #[serde(default)]
     pub enable_failover_toggle: bool,
+    /// Whether to show the project profile switcher on the main page header
+    #[serde(default = "default_show_profile_switcher")]
+    pub show_profile_switcher: bool,
     /// Keep Codex ChatGPT login material in auth.json when switching to third-party providers.
     /// Opt-in: defaults to false so third-party switches cleanly overwrite auth.json.
     #[serde(default)]
@@ -490,6 +493,10 @@ fn default_minimize_to_tray_on_close() -> bool {
     true
 }
 
+fn default_show_profile_switcher() -> bool {
+    true
+}
+
 impl Default for AppSettings {
     fn default() -> Self {
         Self {
@@ -506,6 +513,7 @@ impl Default for AppSettings {
             usage_dashboard_refresh_interval_ms: None,
             stream_check_confirmed: None,
             enable_failover_toggle: false,
+            show_profile_switcher: true,
             preserve_codex_official_auth_on_switch: false,
             unify_codex_session_history: false,
             unify_codex_migrate_existing: None,