Add deck synergy suggestions, a responsive deck layout, and undoable library bulk-add

Suggestion scoring is fully offline (tribal/mechanic/archetype/mana-base
signals derived at ingest, no external synergy database), with an "unusual
picks" mode that surfaces underappreciated cards instead of staples. The
deck page's top panels now use a CSS grid so wide windows don't waste
horizontal space. Library's bulk add-to-deck can clobber existing deck
quantities, so it now offers an undo (snackbar + command palette, the
latter with no timeout) that restores each card's prior state exactly.

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

src-tauri/src/commands.rs

@@ -5,7 +5,10 @@
 use std::path::PathBuf;
 use std::sync::Mutex;
 
-use mtgc_core::{CardRef, Deck, DeckEntry, LibraryCard, LibraryFacets, LibraryFilter, LibraryStats};
+use mtgc_core::{
+    CardRef, CardSuggestion, Deck, DeckEntry, LibraryCard, LibraryFacets, LibraryFilter,
+    LibraryStats,
+};
 use serde::Serialize;
 use tauri::{AppHandle, Emitter, State};
 
@@ -130,6 +133,14 @@ pub fn deck_contents(db: Db, deck_id: i64) -> Res<Vec<DeckEntry>> {
     s.catalog()?.deck_contents(deck_id).map_err(|e| e.to_string())
 }
 
+#[tauri::command]
+pub fn suggest_cards(db: Db, deck_id: i64, offset: i64, unusual: bool) -> Res<Vec<CardSuggestion>> {
+    let s = db.lock().unwrap();
+    s.catalog()?
+        .suggest_cards(deck_id, 50, offset.max(0) as usize, unusual)
+        .map_err(|e| e.to_string())
+}
+
 #[tauri::command]
 pub fn search_library(db: Db, filter: LibraryFilter) -> Res<Vec<LibraryCard>> {
     let s = db.lock().unwrap();

src-tauri/src/lib.rs

@@ -41,6 +41,7 @@ pub fn run() {
             commands::set_deck_commander,
             commands::set_deck_card,
             commands::deck_contents,
+            commands::suggest_cards,
             commands::card_decks,
             commands::export_deck,
             commands::import_deck,