/plugins: Add v2 tabbed marketplace menu (#18222)

This PR moves `/plugins` onto the shared tabbed selection-list
infrastructure and introduces the new v2 menu. The menu now groups
plugins into All Plugins, Installed, OpenAI Curated, and per-marketplace
tabs.

- Rebuild /plugins on top of the shared tabbed selection list
- Add All Plugins, Installed, OpenAI Curated, and per-marketplace tabs
- Preserve active tab and selected-row behavior across popup refreshes
- Add duplicate marketplace tab-label disambiguation
- Update browse-mode popup tests and snapshots

Co-authored-by: Codex <noreply@openai.com>

codex-rs/tui/src/bottom_pane/mod.rs

@@ -120,6 +120,7 @@ mod selection_tabs;
 mod textarea;
 mod unified_exec_footer;
 pub(crate) use feedback_view::FeedbackNoteView;
+pub(crate) use selection_tabs::SelectionTab;
 
 /// How long the "press again to quit" hint stays visible.
 ///
@@ -854,7 +855,6 @@ impl BottomPane {
             .and_then(|view| view.selected_index())
     }
 
-    #[allow(dead_code)]
     pub(crate) fn active_tab_id_for_active_view(&self, view_id: &'static str) -> Option<&str> {
         self.view_stack
             .last()