fix: improve mobile header and board menus (#6715)

* fix: improve mobile header and board menus

* fix: keep mobile header logo condensed

* refactor: share mobile breakpoint handling

packages/ui/src/hooks/index.ts

@@ -1 +1,2 @@
+export * from "./use-is-mobile";
 export * from "./use-translated-mantine-react-table";

packages/ui/src/hooks/use-is-mobile.ts

@@ -0,0 +1,9 @@
+"use client";
+
+import { useMantineTheme } from "@mantine/core";
+import { useMediaQuery } from "@mantine/hooks";
+
+export const useIsMobile = () => {
+  const theme = useMantineTheme();
+  return useMediaQuery(`(max-width: ${theme.breakpoints.sm})`);
+};