bug: bookmarks are not auth-gated

[zeucapua]

Describe the bug
A user can click the bookmark button on each post and the /bookmarks link button on the bottom navigation bar without being logged in. There are no errors to indicate that they have to be logged in.

To Reproduce
Steps to reproduce the behavior:

1. Go to the home page and ensure you're NOT logged in
2. Click the bookmark button on any post
3. See that there are no changes
4. Click the /bookmarks icon link on the bottom navigation bar
5. See an empty page

Expected behavior

• When clicking on a post's bookmark button, there should be an error toast saying they must be logged in (model after the "New Post" circle action button's toast)
• When clicking on the /bookmarks link button, there should be an error toast saying they must be logged in OR the page itself should tell them it's empty because they are not logged in.