fix(frontend): match database management button to workspace management

frontend/src/shell/AppShell.database-management.test.tsx

@@ -63,7 +63,8 @@ test("opens the blank database management surface and returns to the core", asyn
 
   expect(screen.getByRole("main", { name: "Database management" })).toBeVisible();
   expect(databaseManagement).toHaveAttribute("aria-current", "page");
-  expect(databaseManagement).toHaveClass("bg-sidebar-accent", "font-bold");
+  expect(databaseManagement).toHaveClass("w-full");
+  expect(databaseManagement).not.toHaveClass("bg-sidebar-accent");
   expect(screen.queryByRole("textbox", { name: /new question/i })).not.toBeInTheDocument();
 
   await userEvent.click(screen.getByRole("button", { name: "New session" }));

frontend/src/shell/AppShell.tsx

@@ -746,14 +746,9 @@ export function AppShell({ canLogout }: AppShellProps) {
             Workspace management
           </Button>
           <Button
-            variant="ghost"
+            variant="outline"
             size="sm"
-            className={[
-              "w-full justify-start hover:bg-sidebar-accent",
-              activeSurface === "database-management"
-                ? "bg-sidebar-accent font-bold text-sidebar-accent-foreground"
-                : "",
-            ].join(" ")}
+            className="w-full"
             aria-current={activeSurface === "database-management" ? "page" : undefined}
             onClick={() => setActiveSurface("database-management")}
           >