style(LogStreamPanel): match HistoryListPanel button styling

Clear / Export / Copy All on the Logging screen were rendered with the
subtle ToolbarButton helper while History's equivalents use
`Button variant="default"`. Switch all three to the default variant so
the toolbars look identical across screens and mirror the disabling
behavior — each button is now disabled when `entries.length === 0`.

ToolbarButton helper is unused after this change and dropped.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: cliffhall

clients/web/src/components/groups/LogStreamPanel/LogStreamPanel.tsx

@@ -31,11 +31,6 @@ const PanelContainer = Paper.withProps({
   variant: "panel",
 });
 
-const ToolbarButton = Button.withProps({
-  variant: "subtle",
-  size: "sm",
-});
-
 const EmptyCenter = Stack.withProps({
   flex: 1,
   align: "center",
@@ -88,9 +83,27 @@ export function LogStreamPanel({
             checked={autoScroll}
             onChange={onToggleAutoScroll}
           />
-          <ToolbarButton onClick={onClear}>Clear</ToolbarButton>
-          <ToolbarButton onClick={onExport}>Export</ToolbarButton>
-          <ToolbarButton onClick={onCopyAll}>Copy All</ToolbarButton>
+          <Button
+            variant="default"
+            onClick={onClear}
+            disabled={entries.length === 0}
+          >
+            Clear
+          </Button>
+          <Button
+            variant="default"
+            onClick={onExport}
+            disabled={entries.length === 0}
+          >
+            Export
+          </Button>
+          <Button
+            variant="default"
+            onClick={onCopyAll}
+            disabled={entries.length === 0}
+          >
+            Copy All
+          </Button>
         </Group>
       </Group>
       {filteredEntries.length > 0 ? (

clients/web/src/components/screens/LoggingScreen/LoggingScreen.test.tsx

@@ -35,19 +35,36 @@ describe("LoggingScreen", () => {
   it("invokes onClear when clear is clicked", async () => {
     const user = userEvent.setup();
     const onClear = vi.fn();
-    renderWithMantine(<LoggingScreen {...baseProps} onClear={onClear} />);
+    const entries = [
+      { receivedAt: new Date(), params: { level: "info" as const, data: "x" } },
+    ];
+    renderWithMantine(
+      <LoggingScreen {...baseProps} entries={entries} onClear={onClear} />,
+    );
     await user.click(screen.getByRole("button", { name: "Clear" }));
     expect(onClear).toHaveBeenCalledTimes(1);
   });
 
   it("invokes onCopyAll when Copy All is clicked", async () => {
     const user = userEvent.setup();
     const onCopyAll = vi.fn();
-    renderWithMantine(<LoggingScreen {...baseProps} onCopyAll={onCopyAll} />);
+    const entries = [
+      { receivedAt: new Date(), params: { level: "info" as const, data: "x" } },
+    ];
+    renderWithMantine(
+      <LoggingScreen {...baseProps} entries={entries} onCopyAll={onCopyAll} />,
+    );
     await user.click(screen.getByRole("button", { name: "Copy All" }));
     expect(onCopyAll).toHaveBeenCalledTimes(1);
   });
 
+  it("disables Clear / Export / Copy All when there are no entries", () => {
+    renderWithMantine(<LoggingScreen {...baseProps} />);
+    expect(screen.getByRole("button", { name: "Clear" })).toBeDisabled();
+    expect(screen.getByRole("button", { name: "Export" })).toBeDisabled();
+    expect(screen.getByRole("button", { name: "Copy All" })).toBeDisabled();
+  });
+
   it("toggles a single level on level button click", async () => {
     const user = userEvent.setup();
     const entries = [