fix(widgets): make downloads widget table background transparent (#6025)

The MantineReactTable defaults table cell backgrounds to
var(--mantine-color-body) which is opaque. This makes the
downloads widget table block appear solid while the footer
and other widgets correctly show the board's background.

Added a styles.css targeting table elements to force
background-color: transparent, following the same pattern
used by the beszel-system-table widget. Also added
bg=transparent to mantinePaperProps for the Paper wrapper.

packages/widgets/src/downloads/component.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import "../widgets-common.css";
+import "./styles.css";
 
 import { useCallback, useMemo, useState } from "react";
 import type { MantineStyleProp } from "@mantine/core";
@@ -577,7 +578,7 @@ export default function DownloadClientsWidget({
     enableColumnOrdering: isEditMode,
     enableRowVirtualization: true,
     rowVirtualizerOptions: { overscan: 5 },
-    mantinePaperProps: { flex: 1, withBorder: false, shadow: undefined },
+    mantinePaperProps: { flex: 1, withBorder: false, shadow: undefined, bg: "transparent" },
     mantineTableContainerProps: { style: { height: "100%" } },
     mantineTableProps: {
       className: "downloads-widget-table",

packages/widgets/src/downloads/styles.css

@@ -0,0 +1,12 @@
+/* Make the MantineReactTable transparent so the board card's opacity-controlled
+   background shows through. MRT defaults to var(--mantine-color-body) which is opaque. */
+.downloads-widget-table,
+.downloads-widget-table .mantine-Table-table,
+.downloads-widget-table .mantine-Table-thead,
+.downloads-widget-table .mantine-Table-tbody,
+.downloads-widget-table .mantine-Table-tfoot,
+.downloads-widget-table .mantine-Table-tr,
+.downloads-widget-table th,
+.downloads-widget-table td {
+  background-color: transparent !important;
+}