Add user invite codes (#393)

* Add mobile UIs for invite codes

* Update invite code UIs for web

* Finish implementing invite code behaviors (including notifications of invited users)

* Bump deps

* Update web right nav to use real data; also fix lint

src/lib/hooks/useCustomPalette.ts

@@ -0,0 +1,13 @@
+import React from 'react'
+import {useTheme} from 'lib/ThemeContext'
+import {choose} from 'lib/functions'
+
+export function useCustomPalette<T>({light, dark}: {light: T; dark: T}) {
+  const theme = useTheme()
+  return React.useMemo(() => {
+    return choose<T, Record<string, T>>(theme.colorScheme, {
+      dark,
+      light,
+    })
+  }, [theme.colorScheme, dark, light])
+}