fix(workshop): allow concurrent downloads and stop auto-applying

Downloads shared a single active-id guard, so a second theme could not start until the first finished, and completing one immediately applied it over the current theme. Each download now tracks its own progress, runs concurrently, and only adds the theme to the library. The batch-selection bar and checkboxes are removed in favour of the independent buttons.

src/lib/communityThemes.ts

@@ -863,19 +863,27 @@ export async function downloadAndInstallCommunityTheme(
 
   reportProgress('Downloading theme package...', 10);
 
-  const unlistenDownload = await listen<{ received: number; total: number; progress: number }>(
-    'download_progress',
-    (event) => {
-      reportProgress('Downloading theme package...', Math.round(10 + event.payload.progress * 50));
-    }
-  );
+  // Progress events are global, so ignore those belonging to other themes that are
+  // downloading at the same time.
+  const unlistenDownload = await listen<{
+    theme_name: string;
+    received: number;
+    total: number;
+    progress: number;
+  }>('download_progress', (event) => {
+    if (event.payload.theme_name !== theme.name) return;
+    reportProgress('Downloading theme package...', Math.round(10 + event.payload.progress * 50));
+  });
 
-  const unlistenExtract = await listen<{ extracted: number; total: number; progress: number }>(
-    'extract_progress',
-    (event) => {
-      reportProgress('Extracting theme files...', Math.round(60 + event.payload.progress * 38));
-    }
-  );
+  const unlistenExtract = await listen<{
+    theme_name: string;
+    extracted: number;
+    total: number;
+    progress: number;
+  }>('extract_progress', (event) => {
+    if (event.payload.theme_name !== theme.name) return;
+    reportProgress('Extracting theme files...', Math.round(60 + event.payload.progress * 38));
+  });
 
   try {
     try {