feat(peer): remove downloaded game files safely

Downloaded but uninstalled games can still occupy significant disk space. Add a
separate removal path for that state instead of overloading uninstall, which is
reserved for deleting only `local/` installs.

The peer runtime now exposes `RemoveDownloadedGame` with matching lifecycle
and active-operation events. The filesystem delete is intentionally strict: the
id must be a catalog game and a single path component, the target must be a
direct child of the configured game directory, the root must not be a symlink,
it must have a regular root-level `version.ini`, and it must not contain
`local/`, `.local.installing/`, or `.local.backup/`. Only then do we recursively
remove the game root.

The Tauri bridge exposes this as `remove_downloaded_game`, the frontend shows a
matching danger action only for downloaded-but-uninstalled games, and a
confirmation dialog warns that re-downloading can take a long time.

Test Plan:
- git diff --check
- just fmt
- RUSTC_WRAPPER= CARGO_BUILD_RUSTC_WRAPPER= just test
- RUSTC_WRAPPER= CARGO_BUILD_RUSTC_WRAPPER= just clippy
- RUSTC_WRAPPER= CARGO_BUILD_RUSTC_WRAPPER= just build

Refs: user redesign nitpick about removing downloaded uninstalled games

crates/lanspread-tauri-deno-ts/src/windows/MainWindow.tsx

@@ -6,6 +6,7 @@ import { KebabItem } from '../components/topbar/KebabMenu';
 import { ResultsBar } from '../components/grid/ResultsBar';
 import { GameGrid } from '../components/grid/GameGrid';
 import { GameDetailModal } from '../components/modals/GameDetailModal';
+import { ConfirmRemoveDownloadModal } from '../components/modals/ConfirmRemoveDownloadModal';
 import { SettingsDialog } from '../components/modals/SettingsDialog';
 import { NoDirectoryState } from '../components/empty/NoDirectoryState';
 import { EmptyResultsState } from '../components/empty/EmptyResultsState';
@@ -50,6 +51,7 @@ export const MainWindow = () => {
     const thumbnails = useThumbnails();
 
     const [openGameId, setOpenGameId] = useState<string | null>(null);
+    const [removeGameId, setRemoveGameId] = useState<string | null>(null);
     const [settingsOpen, setSettingsOpen] = useState(false);
 
     const counts = useMemo(() => countByFilter(games.games), [games.games]);
@@ -65,6 +67,10 @@ export const MainWindow = () => {
         () => openGameId ? games.games.find(g => g.id === openGameId) ?? null : null,
         [openGameId, games.games],
     );
+    const removeGame = useMemo<Game | null>(
+        () => removeGameId ? games.games.find(g => g.id === removeGameId) ?? null : null,
+        [removeGameId, games.games],
+    );
 
     const pickDirectory = useCallback(async () => {
         const picked = await open({ multiple: false, directory: true });
@@ -84,6 +90,15 @@ export const MainWindow = () => {
         actions.uninstall(game.id);
     }, [actions]);
 
+    const handleRemoveDownload = useCallback((game: Game) => {
+        setRemoveGameId(game.id);
+    }, []);
+
+    const confirmRemoveDownload = useCallback((game: Game) => {
+        actions.removeDownload(game.id);
+        setRemoveGameId(null);
+    }, [actions]);
+
     const kebabItems: ReadonlyArray<KebabItem> = useMemo(() => [
         { kind: 'item', label: 'Settings', onClick: () => setSettingsOpen(true) },
         { kind: 'item', label: 'Refresh library', onClick: () => rescan() },
@@ -153,6 +168,15 @@ export const MainWindow = () => {
                     onClose={() => setOpenGameId(null)}
                     onPrimary={handlePrimary}
                     onUninstall={handleUninstall}
+                    onRemoveDownload={handleRemoveDownload}
+                />
+            )}
+
+            {removeGame && (
+                <ConfirmRemoveDownloadModal
+                    game={removeGame}
+                    onCancel={() => setRemoveGameId(null)}
+                    onConfirm={confirmRemoveDownload}
                 />
             )}