feat(ui): add smallest-first size sort

The redesign only offered a largest-first size sort. Keep the existing `size`
preference value as largest for compatibility with saved settings and add a new
ascending size key for users who want to find small downloads first.

The sort menu now exposes both size directions and the sorter handles the new
smallest-first option directly.

Test Plan:
- git diff --check

Refs: user redesign nitpick about Size (smallest) sort

crates/lanspread-tauri-deno-ts/src/components/topbar/SortMenu.tsx

@@ -6,6 +6,7 @@ import { GameSort } from '../../lib/types';
 const OPTIONS: ReadonlyArray<{ key: GameSort; label: string }> = [
     { key: 'az', label: 'Name (A–Z)' },
     { key: 'size', label: 'Size (largest)' },
+    { key: 'sizeAsc', label: 'Size (smallest)' },
     { key: 'status', label: 'Status' },
 ];
 

crates/lanspread-tauri-deno-ts/src/lib/gameState.ts

@@ -209,6 +209,8 @@ export const applyFilterAndSort = (
             return [...list].sort((a, b) => a.name.localeCompare(b.name));
         case 'size':
             return [...list].sort((a, b) => b.size - a.size);
+        case 'sizeAsc':
+            return [...list].sort((a, b) => a.size - b.size);
         case 'status':
             return [...list].sort(compareByState);
     }

crates/lanspread-tauri-deno-ts/src/lib/types.ts

@@ -60,7 +60,7 @@ export interface GamesListPayload {
 export type GameFilter = 'all' | 'local' | 'installed';
 
 /** Library sort order. */
-export type GameSort = 'az' | 'size' | 'status';
+export type GameSort = 'az' | 'size' | 'sizeAsc' | 'status';
 
 /** Visual state of a card. Derived from install/download flags. */
 export type DerivedState = 'installed' | 'local' | 'none' | 'busy';