feat: batch download

static/app.css

@@ -176,6 +176,29 @@
   }
   .files-header h2 { font-size: 16px; font-weight: 600; }
   .files-header .meta { font-size: 12px; color: var(--text-dim); }
+  .files-header-right {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    flex-wrap: wrap;
+    justify-content: flex-end;
+  }
+  .check-all-wrap {
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
+    font-size: 12px;
+    color: var(--text-dim);
+    cursor: pointer;
+    user-select: none;
+  }
+  .check-all-wrap input {
+    width: 14px;
+    height: 14px;
+    accent-color: var(--primary);
+    cursor: pointer;
+  }
+  .batch-btn { padding: 6px 14px; font-size: 13px; }
 
   /* Quota */
   .quota-wrap { margin-bottom: 16px; }
@@ -214,6 +237,13 @@
     border-radius: 8px;
     margin-bottom: 8px;
   }
+  .file-check {
+    width: 18px;
+    height: 18px;
+    accent-color: var(--primary);
+    cursor: pointer;
+    flex-shrink: 0;
+  }
   .file-icon {
     width: 36px;
     height: 36px;