Deck actions UI, consistent icon buttons, native select fix, sidebar stats

- DeckView: rename/duplicate/delete deck via row-hover icon actions, with
  a ConfirmDialog for delete and PromptDialog (with friendly name-
  collision errors) for rename/duplicate.
- Add a shared IconButton (plus overlay/danger variants) and replace
  every ad hoc close/remove button in the app with it: deck actions,
  remove-card-from-deck (list and tile), clear-commander, the card-
  preview close, and the ingest-progress dismiss.
- Fix native <select> (Group by, Format, In deck): only color/border were
  overridden, leaving native OS chrome (height, arrow, popup) in place.
  Drop appearance and draw a custom chevron so they match text inputs.
- Click-to-preview: show both faces of a double-faced card side by side
  on wide viewports instead of requiring Flip, and size the preview
  images larger overall.
- Sidebar footer: replace the plain "N cards" line with a "Your library"
  panel (unique/copies/decks tiles + a WUBRG color-distribution bar),
  polling get_library_stats while card data is loaded.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -30,9 +30,12 @@ pub fn run() {
             commands::set_owned,
             commands::set_location,
             commands::search_library,
+            commands::get_library_stats,
             commands::list_decks,
             commands::create_deck,
             commands::delete_deck,
+            commands::rename_deck,
+            commands::duplicate_deck,
             commands::set_deck_format,
             commands::set_deck_commander,
             commands::set_deck_card,